Sponsored Content
Full Discussion: IO performance symptoms
Special Forums Hardware Filesystems, Disks and Memory IO performance symptoms Post 302344691 by vada010 on Monday 17th of August 2009 10:12:42 AM
Old 08-17-2009
IO performance symptoms

Does anyone have a good link which outlines symptoms for different performance issues related to IO? I am looking for data I can compare to my IOSTAT or VMSTAT output. For example, I am trying to see if my disk is thrashing..does anyone have output on vmstat or iostat from when there disk was thrashing..

8 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users


Hello, i have changed a slow server with Solaris 7 to a bigger one with Solaris 8 (Sun Ultra 2). Now i have a real bad performance problem (only CPU). Solaris 7 ran with standard FTP and Samba 2.0.7. The new machine is running ProFTP and Samba 2.0.9. There are a lot of NFS Shares and... (5 Replies)
Discussion started by: olso
5 Replies

2. UNIX for Advanced & Expert Users


Hi, 1-in vmstat commande line, in reply, which column is the more important to look and verify if server is very slow ? 2-how can I see how many sessions are opened with the same login ? Many thanks before. (2 Replies)
Discussion started by: big123456
2 Replies

3. UNIX for Advanced & Expert Users


Hi, I have this on a AIX UNIX machine : ps aux| head -20 USER PID %CPU %MEM SZ RSS TTY STAT STIME TIME COMMAND root 516 23.7 0.0 12 15808 - A 19:38:15 903:13 wait root 774 23.7 0.0 12 15808 - A 19:38:15 902:13 wait root 1290 23.6 0.0 ... (2 Replies)
Discussion started by: big123456
2 Replies

4. UNIX for Advanced & Expert Users

I/O performance

i want to determine I/O performance of an executable, but iostat dont give correct results because the disk that i am writing to and reading from, are not physical disk of the host machine, instead of these local disks we are using a network storage. is there any standard way in unix to get... (2 Replies)
Discussion started by: gfhgfnhhn
2 Replies

5. News, Links, Events and Announcements

Announcing collectl - new performance linux performance monitor

About 4 years ago I wrote this tool inspired by Rob Urban's collect tool for DEC's Tru64 Unix. What makes this tool as different as collect was in its day is its ability to run at a low overhead and collect tons of stuff. I've expanded the general concept and even include data not available in... (0 Replies)
Discussion started by: MarkSeger
0 Replies

6. Solaris

best way and best performance

Hi all, I have two storadge 3510 Fc .. with 12 disks 146Gb ..total 1752Gb each storadge. I need to use about 1.4 Tb of it. and want RAID1 .. I need 13 mount points .. So question: for best performance and redundjancy how I must do it. create 13 logical drives on each stordge with same size... (1 Reply)
Discussion started by: samar
1 Replies

7. Solaris

troubleshooting log detailing symptoms/error msgs/fix actions for NIS+ client authent

summary found at bottom. to skip straight to action summary, ctrl+f for <summary> this initially started with trouble changing passwords due to client being unable to authenticate, this was further caused by missing client files. This was transparent to me, so this details the road I took,... (0 Replies)
Discussion started by: ProGrammar
0 Replies

8. Solaris

A DT Message error on login... other symptoms

First let me apologize for joining and posting... but this thing is killing me. I can usually solve these problems myself but I am reaching for help now. I have about 2 years Unix 8 experience but I am by no means an expert but not a newb either. A little background. My system runs a... (8 Replies)
Discussion started by: mpb218
8 Replies
IOSTAT(8)						    BSD System Manager's Manual 						 IOSTAT(8)

iostat -- report I/O statistics SYNOPSIS
iostat [-CUdKIoT?] [-c count] [-n devs] [-w wait] [drives] DESCRIPTION
Iostat displays kernel I/O statistics on terminal, device and cpu operations. The first statistics that are printed are averaged over the system uptime. To get information about the current activity, a suitable wait time should be specified, so that the subsequent sets of printed statistics will be averaged over that time. The options are as follows: -? Display a usage statement and exit. -C Display CPU statistics. This is on by default, unless -d is specified. -c Repeat the display count times. If no wait interval is specified, the default is 1 second. -d Display only device statistics. If this flag is turned on, only device statistics will be displayed, unless -C or -U or -T is also specfied to enable the display of CPU, load average or TTY statistics. -I Display total statstics for a given time period, rather than average statistics for each second during that time period. -K In the blocks transferred display (-o), display block count in kilobytes rather then the device native block size. -n Display up to devs number of devices. iostat will display fewer devices if there aren't devs devices present. -o Display old-style iostat device statistics. Sectors per second, transfers per second, and miliseconds per seek are displayed. If -I is specified, total blocks/sectors, total transfers, and miliseconds per seek are displayed. -T Display TTY statistics. This is on by default, unless -d is specified. -U Display system load averages. This is on by default, unless -d is specified. -w Pause wait seconds between each display. If no repeat count is specified, the default is infinity. Iostat displays its information in the following format: tty tin characters read from terminals tout characters written to terminals devices Device operations. The header of the field is the device name and unit number. iostat will display as many devices as will fit in a standard 80 column screen, or the maximum number of devices in the system, whichever is smaller. If -n is specified on the command line, iostat will display the smaller of the requested number of devices, and the maximum number of devices in the system. To force iostat to display specific drives, their names may be supplied on the command line. iostat will not display more devices than will fit in an 80 column screen, unless the -n argument is given on the command line to specify a maximum number of devices to display, or the list of specified devices exceeds 80 columns. If fewer devices are specified on the command line than will fit in an 80 column screen, iostat will show only the specified devices. The standard iostat device display shows the following statistics: KB/t kilobytes per transfer tps transfers per second MB/s megabytes per second The standard iostat device display, with the -I flag specified, shows the following statistics: KB/t kilobytes per transfer xfrs total number of transfers MB total number of megabytes transferred The old-style iostat display (using -o) shows the following statistics: sps sectors transferred per second tps transfers per second msps average milliseconds per transaction The old-style iostat display, with the -I flag specified, shows the following statistics: blk total blocks/sectors transferred xfr total transfers msps average milliseconds per transaction cpu us % of cpu time in user mode sy % of cpu time in system mode id % of cpu time in idle mode EXAMPLES
iostat -w 1 disk0 disk2 Display statistics for the first and third disk devices device every second ad infinitum. iostat -c 2 Display the statistics for the first four devices in the system twice, with a one second display interval. iostat -Iw 3 Display total statistics every three seconds ad infinitum. iostat -odICTw 2 -c 9 Display total statistics using the old-style output format 9 times, with a two second interval between each measurement/display. The -d flag generally disables the TTY and CPU displays, but since the -T and -C flags are given, the TTY and CPU displays will be displayed. SEE ALSO
fstat(1), netstat(1), nfsstat(1), ps(1), pstat(8) The sections starting with ``Interpreting system activity'' in Installing and Operating 4.3BSD. HISTORY
This version of iostat first appeared in FreeBSD 3.0. BSD
September 27, 2001 BSD

Featured Tech Videos

All times are GMT -4. The time now is 08:28 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy