Wednesday, February 25, 2009

Trouble Shooting Interview Question Solaris

1)What can I do if Solaris won't boot?

You need to boot from your install CD. Insert the Solaris Software CD in your CDROM drive. If your CDROM drive/BIOS isn't bootable, first insert the "Device Configuration Assistant" (DCA) diskette. At the "Boot Solaris" menu, choose "CD."

At the "Type of Installation: Interactive or JumpStart" menu, type "b -s"
Or, after the video configuration, network, time and date you'll notice one of the menu's has a button: [Exit] Select Exit and, when it asks you again "do you want to exit?," just say yes.

Once you're at the UNIX root prompt #, you can mount the boot drive with "mount /dev/dsk/c0t0d0s0 /mnt"" and view anything wrong with the boot drive (omit the "t0" for ATAPI).

2)How do I restore the Solaris boot block without reinstalling?

This may happen when installing a boot manager that comes with another operating system (such as LILO from Linux) or an after-market multi-OS boot manager. These sometimes trample's active partition, which in our case is Solaris. Also, moving the Solaris partition with a partition manager program such as Partition Magic requires reinstalling the Solaris boot block. Before taking these steps, first verify the Solaris partition is active. If it isn't, just make the Solaris partition active and reboot. Otherwise follow the steps below.

1. Boot from CD-ROM and get the root prompt, #, as described in the previous question, 7.1.

2. Determine the controller, disk number, and partition. The boot disk is /dev/rdsk/c?t?d?p? where ? is the controller #, target ID, and disk #, and partition #. Omit "t?" for ATAPI E.g., /dev/rdsk/c0d0p0

3. Verify it's the correct device correct with prtvtoc for the drive: This is VERY important; if it's wrong, you you may hose another partition: prtvtoc /dev/rdsk/c0t0d0p0 (omit "t0" for ATAPI, always use p0, which means the "entire drive"). The prtvtoc prints out the map for the Solaris partition on the hard drive, if found. The partitions shown on the output are actually "slices" within the Solaris partition.

4. Restore the boot block as follows:
/sbin/fdisk -b /usr/lib/fs/ufs/mboot (raw disk dev)
E.g., for SCSI it might be:
/sbin/fdisk -b /usr/lib/fs/ufs/mboot /dev/rdsk/c0t0d0p0
(omit "t0" for ATAPI)

5. Finally, remove your CDROM and diskette media and type "/sbin/shutdown -i6" to reboot. The Solaris Multiple Device Boot Menu should appear after rebooting. If not, you can always to an upgrade (re-)install.
Note: This procedure does NOT make your Solaris partition active again (sometimes needed after installing another operating system, such as Windows, on the same disk), it just writes to your bootblock IN your Solaris partition. To learn more about the Solaris boot process, read the boot(1M) man page.

3)How do I logon as root if the password doesn't work anymore?

Regaining control of a Solaris x86 system where the root password has been lost can be accomplished by the following steps. Note that any savvy user can do this with the proper CD-ROM and diskette. Therefore, of course, physical security of a system is important for machines containing sensitive data.

1. Insert installation boot diskette and installation CD-ROM for Solaris x86.

2. Boot system from the installation floppy and select the CD-ROM as the boot device.

3. Type "b -s" (instead of typing 1 or 2 from the menu) and it'll drop you straight to a root shell, #, (and you'll be in single-user mode).

4. At the root prompt, #, key in the following commands, which will create a directory called hdrive under the /tmp directory and then mount the root hard drive partition under this temporary directory.

5. mkdir /tmp/hdrive

6. mount /dev/dsk/c0t0d0s0 /tmp/hdrive #SCSI; for ATAPI, omit "t0"

7. To use the vi editor, the TERM variable must be defined. Key in the following commands.

8. TERM=at386

9. export TERM

10. Start vi (or some other editor) and load /tmp/hdrive/etc/shadow file:

11. vi /tmp/hdrive/etc/shadow

12. Change the first line of the shadow file that has the root entry to:

13. root::6445::::::

14. Write and quit the vi editor with the "!" override command:

15. :wq!

16. Remove the floppy installation diskette, and reboot the system:

17. /sbin/shutdown -i6

18. When system has rebooted from the hard drive, you can now log in from the Console Login: as root with no password. Just hit enter for the password.

19. After logging in as root, use the passwd command to change the root password and secure the system.

Andreas Pfaffeneder has a simpler suggested to recover the password:
Choose the Failsafe-Boot option (which results in kernel/unix -s), answer "Yes" when you are prompted if / of the installed system should be mounted. Chroot into the system and change the password:
# chroot /a /bin/bash
# passwd
# /sbin/shutdown -i6

4)How can I fix Netscape Communicator to render fonts correctly on S/x86?
This problem occurs with Solaris 2.6 and Netscape Communicator 4.0x, and has since been fixed. Apply patch 106248, which I'm told fixes this problem. A workaround is to add the following two lines to your ~/.xinitrc file:
xset +fp /usr/openwin/lib/X11/fonts/75dpi/
xset fp rehash
Another workaround, if you don't have these fonts, is to go into Netscape Preferences and change the font faces.

5)Why is Solaris always booting into the Device Configuration Assistant (DCA)?

This is usually caused by one of the following:
• You installed Solaris onto a disk other than the primary boot disk.

• You didn't remove your DCA boot diskette or if you didn't remove your installation CD-ROM if it's in a bootable CD-ROM drive.

• File /boot/solaris/bootenv.rc is corrupt or truncated, usually after a hard reboot or reset. This file is setup and used by DCA. It should contain several lines.

To change or set your default boot device, See Sun FAQ 2271-02 at http://access1.Sun.COM/cgi-bin/rinfo2html?227102.faq for instructions. To summarize:

• From the "Boot Solaris" screen, press F4 (Boot Tasks).

• On the "Boot Tasks" screen, press Enter to place an "X" in front of "View/Edit Autoboot Settings."

• In the "View/Edit Autoboot Settings" screen, note that the Default Boot Device will not be set to any valid device. Place an "X" in front of Set Default Boot Device and press F2 (Continue).

• On the Set Default Boot Device screen, place an X in front of the correct disk and press F2 (Continue).

• Arrow up to the Accept Settings and press Enter to mark with an "X". Press F2 (Continue) to return to the Boot Tasks screen.

• Press F3 (Back). It will load appropriate drivers after which you will be at the Boot Solaris screen. Press F2 (Continue) to continue booting

6)Help! I get error 2 or error 8 while applying patches. What do I do?
Don't do anything. Error 2 means you already have the same or newer code. Error 8 means you can't patch some optional packages that haven't been installed, even if you did "everything plus OEM" during the original installation. Other errors, usually from lack of disk space, are explained in the patchadd(1M) man page.

7)I get this error message: "can't get local host's domain name" or "The local host's domain name hasn't been set." What do I do?
This is a NIS message. The easiest way to fix it is to type the following as root:
domainname; domainname >/etc/defaultdomain

8)My system doesn't boot due to superblock problems with the root filesystem. What do I do?

Normally, you reboot in single user mode and run /usr/bin/fsck as root and everything is OK. If you get a message about errors/problems on /dev/dsk/c0d0s0, are told to run fsck manually in single user mode, and get this message:
then you may be able to recover from this if the disk isn't entirely corrupted. The superblock stores important information about the file system. Because it is so important it is duplicated in several places. Hopefully one of the backup superblocks isn't corrupted. To see duplicate locations of superblock, use newfs -Nv. For example, if your root slice is at /dev/dsk/c0d0s0, run this command:
# newfs -Nv /dev/dsk/c0d0s0 You must specify -Nv so you don't clobber your root slice with a new filesystem. Your output should look like this:
# newfs -Nv /dev/dsk/c0d0s0
mkfs -F ufs -o N /dev/rdsk/c0d0s0 614880 63 16 8192 1024 16 10 60 2048 t
0 -1 8
7 n
/dev/rdsk/c0d0s0: 614880 sectors in 610 cylinders of 16 tracks, 63
300.2MB in 39 cyl groups (16 c/g, 7.88MB/g, 3776 i/g)
super-block backups (for fsck -F ufs -o b=#) at:
32, 16224, 32416, 48608, 64800, 80992, 97184, 113376, 129568, 145760,
468576, 484768, 500960, 516128, 532320, 548512, 564704, 580896, 597088,
Note the numbers following "super-block backups." Use one of the numbers in fsck (e.g., 32) and use it with the fsck -F -o b= option:
# fsck -F ufs -o b=32
You may get a message FREE BLK COUNT(S) WRONG IN SUPERBLOCK SALVAGE? or FILE SYSTEM STATE IN SUPERBLOCK IS WRONG; FIX? In either case, type "yes" and press return. You should get a FILE SYSTEM WAS MODIFIED message. Reboot your system. If system complains about shutdown not being found do a halt -q. Now, hopefully, your system will boot up with out any problems.

9)Changing a hostname
The following steps are required to change a Sun system's hostname.
• /etc/hosts.allow (to correct access permissions)
• /etc/dfs/dfstab on this system's NFS servers (to allow proper mount access)
• /etc/vfstab on this system's NFS clients (so they will point at the correct server)
• kerberos configurations
• ethers and hosts NIS maps
• DNS information
• Netgroup information
• cron jobs should be reviewed.
• Other hostname-specific scripts and configuration files.
Additional steps may be required in order to correct issues involving other systems.
Having said all that, the minumum number of changes required are:
• /etc/nodename
• /etc/hosts
• /etc/hostname.*
• /etc/net/*/hosts

10)NFS Troubleshooting
Sun's web pages contain substantial information about NFS services; search for an NFS Administration Guide or NFS Server Performance and Tuning Guide for the version of Solaris you are running. The share_nfs man page contains specific information about export options.
If NFS is not working at all, try the following:
• Make sure that the NFS server daemons are running. In particular, check for statd, lockd, nfsd and rarpd. If the daemons are not running, they can be started by running /etc/init.d/nfs.server start. See Daemons below for information on NFS-related daemons.
• Check the /etc/dfs/dfstab and type shareall.
• Use share or showmount -e to see which filesystems are currently exported, and to whom. showmount -a shows who the server believes is actually mounting which filesystems.
• Make sure that your name service is translating the server and client hostnames correctly on both ends. Check the server logs to see if there are messages regarding failed or rejected mount attempts; check to make sure that the hostnames are correct in these messages.
• Make sure that the /etc/net/*/hosts files on both ends report the correct hostnames. Reboot if these have to be edited.
If you are dealing with a performance issue, check
• Network Issues
• CPU Useage
• Memory Levels
• Disk I/O
• Increase the number of nfsd threads in /etc/init.d/nfs.server if the problem is that requests are waiting for a turn. Note that this does increase memory useage by the kernel, so make sure that there is enough RAM in the server to handle the additional load.
• Where possible, mount filesystem with the ro option to prevent additional, unnecessary attribute traffic.
• If attribute caching does not make sense (for example, with a mail spool), mount the filesystem with the noac option. If nfsstat reports a high getattr level, actimeo may need to be increased (if the attributes do not change too often).
• nfsstat reports on most NFS-related statistics. The nfsstat page includes information on tuning suggestions for different types of problems that can be revealed with nfsstat.
If these steps do not resolve the issue, structural changes may be required:
• cachefs can be used to push some of the load from the NFS server onto the NFS clients. To be useful, cfsadmin should be used to increase maxfilesize for the cache to a value high enough to allow for the caching of commonly-used files. (The default value is 3 Mb.)

11)NFS Client
When a client makes a request to the NFS server, a file handle is returned. The file handle is a 32 byte structure which is interpreted by the NFS server. Commonly, the file handle includes a file system ID, inode number and the generation number of the inode. (The latter can be used to return a "stale file handle" error message if the inode has been freed and re-used between client file accesses.)
If a response is not received for a request, it is resent, but with an incremented xid (transmission ID). This can happen because of congestion on the network or the server, and can be observed with a snoop session between server and client.
The server handles retransmissions differently depending on whether the requests are idempotent (can be executed several times without ill effect) or nonidempotent (cannot be executed several times). Examples of these would include things like reads and getattrs versus writes, creates and removes. The system maintains a cache of nonidempotent requests so that appropriate replies can be returned.
The following daemons play a critical role in NFS service:
• biod: On the client end, handles asynchronous I/O for blocks of NFS files.
• nfsd: Listens and responds to client NFS requests.
• mountd: Handles mount requests.
• lockd: Network lock manager.
• statd: Network status manager

12)Solaris Filesystem Troubleshooting
Filesystem corruption can be detected and often repaired by the format and fsck commands. If the filesystem corruption is not due to an improper system shutdown, the hard drive hardware may need to be replaced.
ufs filesystems contain the following types of blocks:
• boot block: This stores information used to boot the system.
• superblock: Much of the filesystems internal information is stored in these.
• inode: Stores location information about a file--everything except for the file name. The number of inodes in a filesystem can be changed from the default if newfs -i is used to create the filesystem.
• data block: The file's data is stored in these.
The fsck command is run on each filesystem at boot time. This utility checks the internal consistency of the filesystem, and can make simple repairs on its own. More complex repairs require feedback from the root user, either in terms of a "y" keyboard response to queries, or invocation with the -y option.
If fsck cannot determine where a file belongs, the file may be renamed to its inode number and placed in the filesystem's lost+found directory. If a file is missing after a noisy fsck session, it may still be intact in the lost+found directory.
Sometimes the fsck command complains that it cannot find the superblock. Alternative superblock locations were created by newfs at the time that the filesystem was created. The newfs -N command can be invoked to nondestructively discover the superblock locations for the filesystem.
ufs filesystems can carry "state flags" that have the value of fsclean, fsstable, fsactive or fsbad (unknown). These can be used by fsck during boot time to skip past filesystems that are believed to be okay.
The analyze option of format can be used to examine the hard drive for flaws in a nondestructive fashion.
df can be used to check a filesystem's available space. Of particular interest is df -kl, which checks available space for all local filesystems and prints out the statistics in kilobytes. Solaris 10 also allows us to use df -h, which presents the statistics in a more human-friendly form that doesn't require counting digits to decide whether a file is 100M or 1G in size.
du can be used to check space used by a directory. In particular, du -dsk will report useage in kilobytes of a directory and its descendants, without including space totals from other filesystems.
Filesystem Tuning
Filesystem performance can be improved by looking at filesystem caching issues.
The following tuning parameters may be valuable in tuning filesystem performance with tunefs or mkfs/newfs:
• inode count: The default is based upon an assumption of average file sizes of 2 KB. This can be set with mkfs/newfs at the time of filesystem creation.
• time/space optimization: Optimization can be set to allow for fastest performance or most efficient space useage.
• minfree: In Solaris 2.6+, this is set to (64 MB / filesystem size) x 100. Filesystems in earlier OS versions reserved 10%. This parameter specifies how much space is to be left empty in order to preserve filesystem performance.
• maxbpg: This is the maximum number of blocks a file can leave in a single cylinder group. Increasing this limit can improve large file performance, but may have a negative impact on small file performance

14)Filesystem Performance Monitoring
McDougall, Mauro and Gregg suggest that the best way to see if I/O is a problem at all is to look at the amount of time spent on POSIX read() and write() system calls via DTrace. If so, we need to look at the raw disk I/O performance.

As with most of the monitoring commands, the first line of iostat reflects a summary of statistics since boot time. To look at meaningful real-time data, run iostat with a time step (eg iostat 30) and look at the lines that report summaries over the time step intervals.
For Solaris 2.6 and higher, use iostat -xPnce 30 to get information including the common device names of the disk partitions, CPU statistics, error statistics, and extended disk statistics.
For Solaris 2.5.1 and earlier, or for more compact output, use iostat -xc 30 to get the extended disk and CPU statistics.
In either case, the information reported is:
• disk: Disk device name.
• r/s, w/s: Average reads/writes per second.
• Kr/s, Kw/s: Average Kb read/written per second.
• wait: Time spent by a process while waiting for block
(eg disk) I/O to complete. (See Notes on Odd Behavior below.)
• actv: Number of active requests in the hardware queue.
• %w: Occupancy of the wait queue.
• %b: Occupancy of the active queue with the device busy.
• svc_t: Service time (ms). Includes everything: wait time, active queue time, seek rotation, transfer time.
• us/sy: User/system CPU time (%).
• wt: Wait for I/O (%).
• id: Idle time (%).

Notes on Odd Behavior

The "wait" time reported by iostat refers to time spent by a process while waiting for block device (such as disk) I/O to finish. In Solaris 2.6 and earlier, the calculation algorithm sometimes overstates the problem on multi-processor machines, since it does not take into account that an I/O wait on one CPU does not mean that I/O is blocked for processes on the other CPUs. Solaris 7 has corrected this problem.
iostat also sometimes reports excessive svc_t (service time) readings for disks that are very inactive. This is due to the action of fsflush keeping the data in memory and on the disk up-to-date. Since many writes are specified over a very short period of time to random parts of the disk, a queue forms briefly, and the average service time goes up. svc_t should only be taken seriously on a disk that is showing 5% or more activity.

mpstat reports information which is useful in understanding lock contention and CPU loading issues.
mpstat reports the following:
• CPU: Processor ID
• minf: Minor faults
• mjf: Major fault
• xcal: Processor cross-calls (when one CPU wakes up another by interrupting it). If this exceeds 200/second, the application in question may need to be examined.
• intr: Interrupts.
• ithr: Interrupts as threads (except clock).
• csw: Context switches
• icsw: Involuntary context switches (this is probably the more relevant statistic when examining performance issues.)
• migr: Thread migrations to another processor. If the migr measurement of mpstat is greater than 500, rechoose_interval should be sent longer in the kernel.
• smtx: Number of times a CPU failed to obtain a mutex.
• srw: Number of times a CPU failed to obtain a read/write lock on the first try.
• syscl: Number of system calls.
• usr/sys/wt/idl: User/system/wait/idle CPU percentages.

netstat provides useful information regarding traffic flow.
In particular, netstat -i lists statistics for each interface, netstat -s provides a full listing of several counters, and netstat -rs provides routing table statistics. netstat -an reports all open ports.
netstat -k provides a useful summary of several network-related statistics up through Solaris 9, but this option was removed in Solaris 10 in favor of the /bin/kstat command. Through Solaris 9, netstat -k provides a listing of several component kstat statistics.
Here are some of the issues that can be revealed with netstat:
• netstat -i: (Collis+Ierrs+Oerrs)/(Ipkts+Opkts) > 2%: This may indicate a network hardware issue.

• netstat -i: (Collis/Opkts) > 10%: The interface is overloaded. Traffic will need to be reduced or redistributed to other interfaces or servers.

• netstat -i: (Ierrs/Ipkts) > 25%: Packets are probably being dropped by the host, indicating an overloaded network (and/or server). Retransmissions can be dropped by reducing the rsize and wsize mount parameters to 2048 on the clients. Note that this is a temporary workaround, since this has the net effect of reducing maximum NFS throughput on the segment.

• netstat -s: If significant numbers of packets arrive with bad headers, bad data length or bad checksums, check the network hardware.

• netstat -i: If there are more than 120 collisions/second, the network is overloaded. See the suggestions above.

• netstat -i: If the sum of input and output packets is higher than about 600 for a 10Mbs interface or 6000 for a 100Mbs interface, the network segment is too busy. See the suggestions above.
• netstat -r: This form of the command provides the routing table. Make sure that the routes are as you expect them to be.

nfsstat can be used to examine NFS performance.
nfsstat -s reports server-side statistics. In particular, the following are important:
• calls: Total RPC calls received.
• badcalls: Total number of calls rejected by the RPC layer.
• nullrecv: Number of times an RPC call was not available even though it was believed to have been received.
• badlen: Number of RPC calls with a length shorter than that allowed for RPC calls.
• xdrcall: Number of RPC calls whose header could not be decoded by XDR (External Data Representation).
• readlink: Number of times a symbolic link was read.
• getattr: Number of attribute requests.
• null: Null calls are made by the automounter when looking for a server for a filesystem.
• writes: Data written to an exported filesystem.
Sun recommends the following tuning actions for some common conditions:
• writes > 10%: Write caching (either array-based or host-based, such as a Prestoserv card) would speed up operation.
• badcalls >> 0: The network may be overloaded and should be checked out. The rsize and wsize mount options can be set on the client side to reduce the effect of a noisy network, but this should only be considered a temporary workaround.
• readlink > 10%: Replace symbolic links with directories on the server.
• getattr > 40%: The client attribute cache can be increased by setting the actimeo mount option. Note that this is not appropriate where the attributes change frequently, such as on a mail spool. In these cases, mount the filesystems with the noac option.
nfsstat -c reports client-side statistics. The following statistics are of particular interest:
• calls: Total number of calls made.
• badcalls: Total number of calls rejected by RPC.
• retrans: Total number of retransmissions. If this number is larger than 5%, the requests are not reaching the server consistently. This may indicate a network or routing problem.
• badxid: Number of times a duplicate acknowledgement was received for a single request. If this number is roughly the same as badcalls, the network is congested. The rsize and wsize mount options can be set on the client side to reduce the effect of a noisy network, but this should only be considered a temporary workaround.
If on the other hand, badxid=0, this can be an indication of a slow network connection.
• timeout: Number of calls that timed out. If this is roughly equal to badxid, the requests are reaching the server, but the server is slow.
• wait: Number of times a call had to wait because a client handle was not available.
• newcred: Number of times the authentication was refreshed.
• null: A large number of null calls indicates that the automounter is retrying the mount frequently. The timeo parameter should be changed in the automounter configuration.
nfsstat -m (from the client) provides server-based performance data.
• srtt: Smoothed round-trip time. If this number is larger than 50ms, the mount point is slow.
• dev: Estimated deviation.
• cur: Current backed-off timeout value.
• Lookups: If cur>80 ms, the requests are taking too long.
• Reads: If cur>150 ms, the requests are taking too long.
• Writes: If cur>250 ms, the requests are taking too long.
In Unix, every object is either a file or a process. With the /proc virtual file system, even processes may be treated like files.
/proc (or procfs) is a virtual file system that allows us to examine processes like files. This means that /proc allows us to use file-like operations and intuitions when looking at processes. /proc does not occupy disk space; it is located in working memory. This structure was originally designed as a programming interface for writing debuggers, but it has grown considerably since then.
To avoid confusion, we will refer to the virtual file system as /proc or procfs. The man page for procfs is proc(4). proc, on the other hand, will be used to refer to the process data structure discussed in the Process Structure page.
Under /proc is a list of numbers, each of which is a Process ID (PID) for a process on our system. Under these directories are subdirectories referring to the different components of interest of each process. This directory structure can be examined directly, but we usually prefer to use commands written to extract information from this structure. These are known as the p-commands.
• pcred: Display process credentials (eg EUID/EGID, RUID/RGID, saved UIDs/GIDs)
• pfiles: Reports fstat() and fcntl() information for all open files. This includes information on the inode number, file system, ownership and size.
• pflags: Prints the tracing flags, pending and held signals and other /proc status information for each LWP.
• pgrep: Finds processes matching certain criteria.
• pkill: Kills specified processes.
• pldd: Lists dynamic libraries linked to the process.
• pmap: Prints process address space map.
• prun: Starts stopped processes.
• prstat: Display process performance-related statistics.
• ps: List process information.
• psig: Lists signal actions.
• pstack: Prints a stack trace for each LWP in the process.
• pstop: Stops the process.
• ptime: Times the command; does not time children.
• ptree: Prints process genealogy.
• pwait: Wait for specified processes to complete.
• pwdx: Prints process working directory.
prstat Example 1
CPU Saturation is can be directly measured via prstat. (Saturation refers to a situation where there is not enough CPU capacity to adequately handle requests for processing resources.) Saturation can be measured directly by looking at the CPU latency time for each thread reported by prstat -mL. (LAT is reported as a percentage of the time that a thread is waiting to use a processor.)
This example shows the prstat -mL output from a single-CPU system that has been overloaded. Notice the load average and LAT numbers.
2724 root 24 0.2 0.0 0.0 0.0 0.0 2.2 74 284 423 361 0 gzip/1
2729 root 21 0.3 0.0 0.0 0.0 0.0 3.3 75 396 564 518 0 gzip/1
2733 root 20 0.3 0.0 0.0 0.0 0.0 5.3 75 391 514 484 0 gzip/1
2737 root 14 0.2 0.0 0.0 0.0 0.0 4.1 81 176 415 383 0 gzip/1
2730 root 3.3 0.3 0.0 0.0 0.0 0.0 96 0.7 602 258 505 0 gunzip/1
2734 root 2.9 0.3 0.0 0.0 0.0 0.0 92 4.5 522 280 457 0 gunzip/1
2738 root 2.7 0.2 0.0 0.0 0.0 0.0 93 3.9 377 147 370 0 gunzip/1
2725 root 2.4 0.2 0.0 0.0 0.0 0.0 95 2.4 495 179 355 0 gunzip/1
2728 root 0.1 1.4 0.0 0.0 0.0 0.0 97 1.7 769 11 2K 0 tar/1
2732 root 0.1 1.3 0.0 0.0 0.0 0.0 99 0.2 762 14 2K 0 tar/1
2723 root 0.0 1.1 0.0 0.0 0.0 0.0 99 0.1 564 7 1K 0 tar/1
2731 root 0.3 0.4 0.0 0.0 0.0 0.0 98 1.2 754 3 1K 0 tar/1
2735 root 0.3 0.4 0.0 0.0 0.0 0.0 98 0.9 722 0 1K 0 tar/1
2736 root 0.0 0.6 0.0 0.0 0.0 0.0 99 0.0 341 2 1K 0 tar/1
2726 root 0.3 0.3 0.0 0.0 0.0 0.0 98 1.0 473 145 1K 0 tar/1
2739 root 0.2 0.2 0.0 0.0 0.0 0.0 99 0.3 335 1 664 0 tar/1
2749 scromar 0.0 0.1 0.0 0.0 0.0 0.0 100 0.0 23 0 194 0 prstat/1
337 root 0.0 0.0 0.0 0.0 0.0 0.0 100 0.0 6 0 36 6 xntpd/1
2716 scromar 0.0 0.0 0.0 0.0 0.0 0.0 100 0.0 3 1 21 0 sshd/1
124 root 0.0 0.0 0.0 0.0 0.0 0.0 100 0.0 3 0 17 0 picld/4
119 root 0.0 0.0 0.0 0.0 0.0 0.0 100 0.0 21 0 63 0 nscd/26
Total: 51 processes, 164 lwps, load averages: 4.12, 2.13, 0.88
prstat Example 2
In this case, we sort prstat output to look for the processes with heavy memory utilization:
# prstat -s rss
471 juser 125M 58M sleep 59 0 4:26:46 0.6% java/17
200 daemon 62M 55M sleep 59 0 0:01:21 0.0% nfsmapid/4
18296 juser 116M 39M sleep 26 11 0:05:36 0.1% java/23
254 root 3968K 1016K sleep 59 0 0:00:03 0.0% sshd/1
Total: 47 processes, 221 lwps, load averages: 0.20, 0.21, 0.20
Other Usage Examples
# ps -ef | grep more | grep -v grep
root 18494 8025 0 08:53:09 pts/3 0:00 more
# pgrep more
# pmap -x 18494
18494: more
Address Kbytes RSS Anon Locked Mode Mapped File
00010000 32 32 - - r-x-- more
00028000 8 8 8 - rwx-- more
0002A000 16 16 16 - rwx-- [ heap ]
FF200000 864 824 - - r-x--
FF2E8000 32 32 32 - rwx--
FF2F0000 8 8 8 - rwx--
FF300000 16 16 - - r-x--
FF312000 16 16 16 - rwx--
FF330000 8 8 - - r-x--
FF340000 8 8 8 - rwx-- [ anon ]
FF350000 168 104 - - r-x--
FF38A000 32 32 24 - rwx--
FF392000 8 8 8 - rwx--
FF3A0000 24 16 16 - rwx-- [ anon ]
FF3B0000 184 184 - - r-x--
FF3EE000 8 8 8 - rwx--
FF3F0000 8 8 8 - rwx--
FFBFC000 16 16 16 - rw--- [ stack ]
-------- ------- ------- ------- -------
total Kb 1456 1344 168 -
# pstack 18494
18494: more
ff2c0c7c read (2, ffbff697, 1)
00015684 ???????? (0, 1, 43858, ff369ad4, 0, 28b20)
000149a4 ???????? (ffbff82f, 28400, 15000000, 28af6, 0, 28498)
00013ad8 ???????? (0, 28b10, 28c00, 400b0, ff2a4a74, 0)
00012780 ???????? (2a078, ff393050, 0, 28b00, 2a077, 6b)
00011c68 main (28b10, ffffffff, 28c00, 0, 0, 1) + 684
000115cc _start (0, 0, 0, 0, 0, 0) + 108
# pfiles 18494
18494: more
Current rlimit: 256 file descriptors
0: S_IFIFO mode:0000 dev:292,0 ino:2083873 uid:0 gid:0 size:0
1: S_IFCHR mode:0620 dev:284,0 ino:12582922 uid:1000 gid:7 rdev:24,3
2: S_IFCHR mode:0620 dev:284,0 ino:12582922 uid:1000 gid:7 rdev:24,3
# pcred 18494
18494: e/r/suid=0 e/r/sgid=0
groups: 0 1 2 3 4 5 6 7 8 9 12

The word "sar" is used to refer to two related items:
1. The system activity report package
2. The system activity reporter
System Activity Report Package
This facility stores a great deal of performance data about a system. This information is invaluable when attempting to identify the source of a performance problem.
The Report Package can be enabled by uncommenting the appropriate lines in the sys crontab. The sa1 program stores performance data in the /var/adm/sa directory. sa2 writes reports from this data, and sadc is a more general version of sa1.
In practice, I do not find that the sa2-produced reports are terribly useful in most cases. Depending on the issue being examined, it may be sufficient to run sa1 at intervals that can be set in the sys crontab.
Alternatively, sar can be used on the command line to look at performance over different time slices or over a constricted period of time:

sar -A -o outfile 5 2000

(Here, "5" represents the time slice and "2000" represents the number of samples to be taken. "outfile" is the output file where the data will be stored.)
The data from this file can be read by using the "-f" option (see below).

System Activity Reporter
sar has several options that allow it to process the data collected by sa1 in different ways:
• -a: Reports file system access statistics. Can be used to look at issues related to the DNLC.

o iget/s: Rate of requests for inodes not in the DNLC. An iget will be issued for each path component of the file's path.

o namei/s: Rate of file system path searches. (If the directory name is not in the DNLC, iget calls are made.)

o dirbk/s: Rate of directory block reads.

• -A: Reports all data.

• -b: Buffer activity reporter:

o bread/s, bwrit/s: Transfer rates (per second) between system buffers and block devices (such as disks).

o lread/s, lwrit/s: System buffer access rates (per second).

o %rcache, %wcache: Cache hit rates (%).

o pread/s, pwrit/s: Transfer rates between system buffers and character devices.

• -c: System call reporter:

o scall/s: System call rate (per second).

o sread/s, swrit/s, fork/s, exec/s: Call rate for these calls (per second).

o rchar/s, wchar/s: Transfer rate (characters per second).

• -d: Disk activity (actually, block device activity):

o %busy: % of time servicing a transfer request.

o avque: Average number of outstanding requests.

o r+w/s: Rate of reads+writes (transfers per second).

o blks/s: Rate of 512-byte blocks transferred (per second).

o avwait: Average wait time (ms).

o avserv: Average service time (ms). (For block devices, this includes seek rotation and data transfer times. Note that the iostat svc_t is equivalent to the avwait+avserv.)

• -e HH:MM: CPU useage up to time specified.

• -f filename: Use filename as the source for the binary sar data. The default is to use today's file from /var/adm/sa.

• -g: Paging activity (see "Paging" for more details):

o pgout/s: Page-outs (requests per second).

o ppgout/s: Page-outs (pages per second).

o pgfree/s: Pages freed by the page scanner (pages per second).

o pgscan/s: Scan rate (pages per second).

o %ufs_ipf: Percentage of UFS inodes removed from the free list while still pointing at reuseable memory pages. This is the same as the percentage of igets that force page flushes.

• -i sec: Set the data collection interval to i seconds.

• -k: Kernel memory allocation:

o sml_mem: Amount of virtual memory available for the small pool (bytes). (Small requests are less than 256 bytes)

o lg_mem: Amount of virtual memory available for the large pool (bytes). (512 bytes-4 Kb)

o ovsz_alloc: Memory allocated to oversize requests (bytes). Oversize requests are dynamically allocated, so there is no pool. (Oversize requests are larger than 4 Kb)

o alloc: Amount of memory allocated to a pool (bytes). The total KMA useage is the sum of these columns.

o fail: Number of requests that failed.

• -m: Message and semaphore activities.

o msg/s, sema/s: Message and semaphore statistics (operations per second).

• -o filename: Saves output to filename.

• -p: Paging activities.

o atch/s: Attaches (per second). (This is the number of page faults that are filled by reclaiming a page already in memory.)

o pgin/s: Page-in requests (per second) to file systems.

o ppgin/s: Page-ins (per second). (Multiple pages may be affected by a single request.)

o pflt/s: Page faults from protection errors (per second).

o vflts/s: Address translation page faults (per second). (This happens when a valid page is not in memory. It is comparable to the vmstat-reported page/mf value.)

o slock/s: Faults caused by software lock requests that require physical I/O (per second).

• -q: Run queue length and percentage of the time that the run queue is occupied.

• -r: Unused memory pages and disk blocks.

o freemem: Pages available for use (Use pagesize to determine the size of the pages).

o freeswap: Disk blocks available in swap (512-byte blocks).

• -s time: Start looking at data from time onward.

• -u: CPU utilization.

o %usr: User time.

o %sys: System time.

o %wio: Waiting for I/O (does not include time when another process could be schedule to the CPU).

o %idle: Idle time.

• -v: Status of process, inode, file tables.

o proc-sz: Number of process entries (proc structures) currently in use, compared with max_nprocs.

o inod-sz: Number of inodes in memory compared with the number currently allocated in the kernel.

o file-sz: Number of entries in and size of the open file table in the kernel.

o lock-sz: Shared memory record table entries currently used/allocated in the kernel. This size is reported as 0 for standards compliance (space is allocated dynamically for this purpose).

o ov: Overflows between sampling points.

• -w: System swapping and switching activity.

o swpin/s, swpot/s, bswin/s, bswot/s: Number of LWP transfers or 512-byte blocks per second.

o pswch/s: Process switches (per second).

• -y: TTY device activity.

o rawch/s, canch/s, outch/s: Input character rate, character rate processed by canonical queue, output character rate.

o rcvin/s, xmtin/s, mdmin/s: Receive, transmit and modem interrupt rates.

The first line of vmstat represents a summary of information since boot time. To obtain useful real-time statistics, run vmstat with a time step (eg vmstat 30).
The vmstat output columns are as follows use the pagesize command to determine the size of the pages):
• procs or kthr/r: Run queue length.
• procs or kthr/b: Processes blocked while waiting for I/O.
• procs or kthr/w: Idle processes which have been swapped.
• memory/swap: Free, unreserved swap space (Kb).
• memory/free: Free memory (Kb). (Note that this will grow until it reaches lotsfree, at which point the page scanner is started. See "Paging" for more details.)
• page/re: Pages reclaimed from the free list. (If a page on the free list still contains data needed for a new request, it can be remapped.)
• page/mf: Minor faults (page in memory, but not mapped). (If the page is still in memory, a minor fault remaps the page. It is comparable to the vflts value reported by sar -p.)
• page/pi: Paged in from swap (Kb/s). (When a page is brought back from the swap device, the process will stop execution and wait. This may affect performance.)
• page/po: Paged out to swap (Kb/s). (The page has been written and freed. This can be the result of activity by the pageout scanner, a file close, or fsflush.)
• page/fr: Freed or destroyed (Kb/s). (This column reports the activity of the page scanner.)
• page/de: Freed after writes (Kb/s). (These pages have been freed due to a pageout.)
• page/sr: Scan rate (pages). Note that this number is not reported as a "rate," but as a total number of pages scanned.
• disk/s#: Disk activity for disk # (I/O's per second).
• faults/in: Interrupts (per second).
• faults/sy: System calls (per second).
• faults/cs: Context switches (per second).
• cpu/us: User CPU time (%).
• cpu/sy: Kernel CPU time (%).
• cpu/id: Idle + I/O wait CPU time (%).

vmstat -i reports on hardware interrupts.
vmstat -s provides a summary of memory statistics, including statistics related to the DNLC, inode and rnode caches.
vmstat -S reports on swap-related statistics such as:
• si: Swapped in (Kb/s).
• so: Swap outs (Kb/s).
(Note that the man page for vmstat -s incorrectly describes the swap queue length. In Solaris 2, the swap queue length is the number of idle swapped-out processes. (In SunOS 4, this referred to the number of active swapped-out processes.)

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