io_tokens?
io_count=5372 io_rate=0 io_tokens=72548 token_refill=512 token_max=400000
[root@li8-42 ~]# cat /proc/io_status
io_count=5464 io_rate=64 io_tokens=75528 token_refill=512 token_max=400000
[root@li8-42 ~]# cat /proc/io_status
io_count=5535 io_rate=0 io_tokens=78529 token_refill=512 token_max=400000
[root@li8-42 ~]# cat /proc/io_status
io_count=5574 io_rate=39 io_tokens=80538 token_refill=512 token_max=400000
[root@li8-42 ~]# cat /proc/io_status
io_count=5613 io_rate=0 io_tokens=92787 token_refill=512 token_max=400000
Why would my tokens be so low after a reboot? And what can I do to help my linode? Pretty much I have one message board with an average of 15-20 people online at a time …. a few coppermine photo galleries, and 2 email accounts using SquirrelMail?
13 Replies
vmstat -s
ps aux
@pclissold:
Post the output of
vmstat -s````
[root@li8-42 ~]# vmstat -s
75388 total memory
24420 used memory
7512 active memory
8492 inactive memory
50968 free memory
3352 buffer memory
12604 swap cache
365560 total swap
0 used swap
365560 free swap
313 non-nice user cpu ticks
0 nice user cpu ticks
1052 system cpu ticks
12593 idle cpu ticks
0 IO-wait cpu ticks
0 IRQ cpu ticks
0 softirq cpu ticks
14209 pages paged in
7840 pages paged out
1 pages swapped in
0 pages swapped out
19674 interrupts
6919 CPU context switches
1141667865 boot time
606 forks
````
@untitled9:
Or the following (as root) to see what process could be responsible for chewing through your io_tokens:
ps aux
root 1 0.0 0.7 1608 600 ? S 12:57 0:00 init [3]
root 2 0.0 0.0 0 0 ? S 12:57 0:00 [keventd]
root 3 0.0 0.0 0 0 ? SN 12:57 0:00 [ksoftirqd_CPU0]
root 4 0.0 0.0 0 0 ? S 12:57 0:00 [kswapd]
root 5 0.0 0.0 0 0 ? S 12:57 0:00 [bdflush]
root 6 0.0 0.0 0 0 ? S 12:57 0:00 [kupdated]
root 7 0.0 0.0 0 0 ? S 12:57 0:00 [jfsIO]
root 8 0.0 0.0 0 0 ? S 12:57 0:00 [jfsCommit]
root 9 0.0 0.0 0 0 ? S 12:57 0:00 [jfsSync]
root 10 0.0 0.0 0 0 ? S 12:57 0:00 [xfsbufd]
root 11 0.0 0.0 0 0 ? S 12:57 0:00 [xfslogd/0]
root 12 0.0 0.0 0 0 ? S 12:57 0:00 [xfsdatad/0]
root 13 0.0 0.0 0 0 ? S< 12:57 0:00 [mdrecoveryd]
root 14 0.0 0.0 0 0 ? S 12:57 0:00 [kjournald]
root 399 0.0 1.3 2028 992 ? Ss 12:58 0:00 /sbin/dhclient -1
root 445 0.0 0.9 1612 696 ? Ss 12:58 0:00 syslogd -m 0
root 449 0.0 0.6 1452 460 ? Ss 12:58 0:00 klogd -x
root 479 0.1 2.1 3920 1652 ? Ss 12:58 0:00 /usr/sbin/sshd
root 489 0.0 1.1 2064 832 ? Ss 12:58 0:00 xinetd -stayalive
root 498 0.0 1.2 3624 968 ? S 12:58 0:00 /usr/sbin/vsftpd
root 516 0.0 4.1 7620 3160 ? Ss 12:58 0:00 sendmail: accepti
smmsp 524 0.0 3.4 6736 2636 ? Ss 12:58 0:00 sendmail: Queue r
root 534 0.0 1.0 3672 808 ? Ss 12:58 0:00 crond
xfs 557 0.0 1.6 2712 1216 ? Ss 12:58 0:00 xfs -droppriv -da
daemon 566 0.0 0.8 1552 628 ? Ss 12:58 0:00 /usr/sbin/atd
root 573 0.0 0.5 1436 428 tty0 Ss+ 12:58 0:00 /sbin/mingetty tt
root 574 0.1 2.8 6776 2156 ? Ss 12:59 0:00 sshd: root@pts/0
root 576 0.0 1.9 4348 1452 pts/0 Ss 12:59 0:00 -bash
root 608 0.0 1.0 2292 768 pts/0 R+ 13:01 0:00 ps aux
My guess is that UML might retain the value of iotokens even across a reboot (although that's only a guess, please don't quote me on that), in which case you should do these commands again when the iotokens get low again.
The other option might be to take a look at the boot-up sequence. There could be something there.
I have noticed a weird trend! When I go to use SquirrelMail … my server slows down a LOT!!! And even get's to the point where I can't ssh into it. Could my multiple uses or SquirrelMail be causing it.?
1) you have a large mailbox (>10M) and you open it.
2) You have "Enable Unread Message Notification" set to all mailboxes and you have a lot of mailboxes.
Ie. you use IO-tokens for regular file system I/O as well, not only swapping activity.
Cheers,
Risto
I used this for a partition that holds seeds for BitTorrent, and it made a huge difference - I only start running low on tokens when the seed gets very close to 100%, and I don't run completely out; under ext3 it was running OUT of tokens long before.
@rodman:
Thanks for the quick response!!!!
I have noticed a weird trend! When I go to use SquirrelMail … my server slows down a LOT!!! And even get's to the point where I can't ssh into it. Could my multiple uses or SquirrelMail be causing it.?
Most likely it's your imap server not squirrelmail. Use dovecot instead of the default imapd, it's better.
@rodman:
Why would my tokens be so low after a reboot?
Because they start from zero when the machine comes up?
Either way, it's likely to be low right after boot.
Squirrelmail opens a new connection to your IMAP server for just about every operation - this very quickly spawns a lot of IMAP processes which will eat memory and io_tokens.
Using an imap proxy means squirrelmail generally only spawns 1 imap service per user, as the proxy keeps that session open and reuses it for each new request from squirrelmail.
@TehDan:
Using an imap proxy means squirrelmail generally only spawns 1 imap service per user, as the proxy keeps that session open and reuses it for each new request from squirrelmail.
I didn't know about that, that's handy, thanks.
If you are using CourierIMAP with vpopmail running on a MySQL database, it can make for a major workload on your Linode for every request/action taken in Squirrelmail for the fact that your Linode would be paging in and out memory for Apache, PHP, CourierIMAP, vpopmail, and MySQL with every single request. I'd use both the suggestion that TehDan made, as well as reconfiguring your vpopmail to use a different database format if you don't have a lot of users. MySQL with vpopmail is only really necessary on systems with lots of users, thousand+ I'd guess, which as you mentioned is not your case. That would also remove vpopmail's dependancy on MySQL keeping it running if MySQL isn't available.