Visit Our UNIX and Linux User Community


IO performance symptoms


 
Thread Tools Search this Thread
Special Forums Hardware Filesystems, Disks and Memory IO performance symptoms
# 1  
Old 08-17-2009
IO performance symptoms

Hello,
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..
# 2  
Old 08-17-2009
would be more helpfull if you post your output and try to explain where your problems are...
# 3  
Old 08-18-2009
Vada,

disks are only thrashing when you are very low in memory and your systems is permanently paging in and out.

Disks being busy up to 70% is normal on AIX and no reason for concern ... are you trying to investigate high IO waits from cpu? What kind of applications do you run?

I agree with DukeNuke, it would be more helpful if we could see your stats to tell you more than fishing in the dark.

Rgds
zxmaus
# 4  
Old 08-24-2009
Stats are posted below.

IOSTAT:
Code:
avg-cpu:  %user   %nice    %sys %iowait   %idle
           0.75    0.00    3.33   22.56   73.36

Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
sda         38.00  59.33 500.00 12.33 19373.33  573.33  9686.67   286.67    38.93     1.52    2.96   1.76  90.00
sdb          0.00  76.67  1.00 39.33    5.33  760.00     2.67   380.00    18.98     2.73  634.89   3.41  13.77

avg-cpu:  %user   %nice    %sys %iowait   %idle
           1.08    0.00    4.41   28.73   65.78

Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
sda         20.33   0.00 506.00  0.67 25728.00    5.33 12864.00     2.67    50.79     1.29    2.55   1.88  95.40
sdb          0.00 4528.33  0.00 89.33    0.00 36949.33     0.00 18474.67   413.61    43.44  486.30   4.16  37.20

MPSTAT:
Code:
04:00:20 AM  CPU   %user   %nice %system %iowait    %irq   %soft   %idle    intr/s
04:00:21 AM  all    2.50    0.00    5.75   21.00    0.00    0.00   70.75   2102.02
04:00:22 AM  all    0.00    0.00    1.75   23.31    0.00    0.25   74.69   1784.00
04:00:23 AM  all    0.50    0.00    2.49   22.94    0.25    0.00   73.82   1779.00
Average:     all    1.00    0.00    3.33   22.42    0.08    0.08   73.08   1887.63

VMSTAT:
Code:
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
12  2 1416976  45892 423720 12917860    0    0    16    28    1     1  1  1 98  0
 0  1 1416976  24188 424548 12941932    0   92 14264   656 2082  4831  3  6 71 21
 0  1 1417020  20924 424868 12945332    0  484  8136  1344 1785  4556  0  2 75 23

SAR -B:
Code:
03:30:01 AM  pgpgin/s pgpgout/s   fault/s  majflt/s
03:40:01 AM      0.38     41.41   3438.90      0.01
03:50:01 AM      0.09     47.06   3719.47      0.00
04:00:01 AM   1811.48   2079.85   3900.20      0.01
Average:       603.94    722.73   3686.15      0.01

04:02:40 AM       LINUX RESTART


Last edited by vada010; 08-24-2009 at 10:21 PM..

Previous Thread | Next Thread
Test Your Knowledge in Computers #763
Difficulty: Medium
L4 caches are currently very common in computer systems.
True or False?

8 More Discussions You Might Find Interesting

1. 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

2. 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

3. 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

4. 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

5. 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

6. UNIX for Advanced & Expert Users

performance

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

7. UNIX for Advanced & Expert Users

performance

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

8. UNIX for Advanced & Expert Users

Performance

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

Featured Tech Videos