Linode.com Forum

[the_dane]

Have a Linode 80 on host 55. Performance is terrible, and can't figure out why. SSH easily takes 5+ seconds. Rendering a page with just php_info() the same. Are typical simple page with mysql-queries and so on happily takes far far over a minute. Kindda unsatisfactory.

While I may not have super-optimized every detail, this is still scaringly slow. It is typical Apache2+PHP4.4+eaccelerator+Mysql4 setup on a small debian stable.

`cat /proc/io_status` during page load:
Code:
io_count=3344568 io_rate=115 io_tokens=399998 token_refill=512 token_max=400000

`vmstat 1` during page load:
Code:
procs -----------memory----------       ---swap-- -----io---- --system-- ----cpu----
 r  b   swpd   free   buff  cache     si   so    bi    bo   in    cs us sy id wa
 1  4 132576   1632   2468   5512    0    0     0     0  109    21  0  0 100  0
 0  4 132572   1616   2468   5516   12   0    13   14  150   24  0  0 100  0
 0  4 132572   1616   2468   5516    0    0     0     0  111    20  0  0 100  0
 0  4 132568   1564   2480   5548    0    0    30    1  118    27  1  3 96  0
 0  6 132568   1528   2480   5564    0    0    20    0  128    22  0  0 100  0


Any ideas?

PS. Have observed this over several weeks with host-load from low to maximum.

[rko]

Check your DNS. It might be trying to resolve your IP and can't find it.

[schmichael]

Your swap usage looks a little high, but it doesn't look like swapping is hurting your performance because your IO tokens and si/so numbers look good.

Are you sure those vmstat numbers are from when a page was actually loading? Because it looks like your system was nearly idle.

It almost makes me wonder if it is some sort of network issue because your system looks pretty calm. Only your memory looks used, but that should only drastically affect performance when it swaps heavily which it isn't appearing to do.

[the_dane]

Yeah, it was during page load. Have checked DNS setup too.

What I have noticed, though, is that hostload tends to be maximum for extended periods, during which it is almost impossible for me to get in contact with my system.

As I understand it, host load is the cummulative load from all the virtual servers hosted. Could I have run into several Gentoo-users? (I have myself used gentoo :) ). Yet I should still at least have the guaranteed CPU/RAM/Bandwith.

I can understand I don't get superperformance, but should still be able to do minimum stuff like editing files without waiting for 5-10 seconds.

/me still wonders whether he has fscked up somewhere or is just unfortunate.

[Raayat]

I have also been having terrible interactivity problems with my Linode 80 on host 55. I've had other Linode 80's before (host 37? maybe?) and never had this much of a problem.

I have nothing serious running. Delay happens most often at the password prompt, for some reason, but even the shortest commands can take 5-10 seconds.

(Yes, my sshd_config has "ReverseMappingCheck no")