Ask HN: server I/O spike

#1

Post by joaquin_win » Sun, Nov 13, 2011, 7:42 PM UTC

I have an app on linode and they sent me an email letting me know of a spike in disk I/o that lasted about 2 hour ad now it's back to normal.

What should I look at when diagnosing what happened?

Weird things at first glance:

1) A spike of incoming network traffic happened at 22:00 2) A spike of outgoing network traffic between 2:00 to 4:00 3)Disk I/O between 6:00 and 8:00

Re: Ask HN: server I/O spike

#2

Post by rhizome » Sun, Nov 13, 2011, 7:53 PM UTC

Check your logs to find out what was going on.

Re: Ask HN: server I/O spike

#3

Post by onur » Sun, Nov 13, 2011, 7:55 PM UTC

You can check the access logs of your server. Probably this is caused by a bot crawling your site and you will see the same IP over and over there. But I'm totally assuming you have a site hosted there which has some kind of database dependence and lots of pages to crawl.

Re: Ask HN: server I/O spike

#4

Post by joaquin_win » Sun, Nov 13, 2011, 8:44 PM UTC

onur wrote: post #3

You can check the access logs of your server. Probably this is caused by a bot crawling your site and you will see the same IP over and over there. But I'm totally assuming you have a site hosted there which has some kind of database dependence and lots of pages to crawl.

Thanks, Any tools to help me along?

Re: Ask HN: server I/O spike

#5

Post by eps » Sun, Nov 13, 2011, 8:44 PM UTC

rhizome wrote: post #2

Check your logs to find out what was going on.

Check your cron jobs too, including those run under non-root accounts.

Re: Ask HN: server I/O spike

#6

Post by flannell » Sun, Nov 13, 2011, 10:07 PM UTC

Yep, same for me. I've just setup a Linode server today in their London DC.

Re: Ask HN: server I/O spike

#7

Post by flannell » Mon, Nov 14, 2011, 9:13 AM UTC

flannell wrote: post #6

Yep, same for me. I've just setup a Linode server today in their London DC.

Sorry, meant to say it happened to me to! Same time and everything.

Re: Ask HN: server I/O spike

#8

Post by joaquin_win » Mon, Nov 14, 2011, 3:08 PM UTC

flannell wrote: post #7

flannell wrote: post #6

Yep, same for me. I've just setup a Linode server today in their London DC.

Sorry, meant to say it happened to me to! Same time and everything.

That's weird, do you think it's related? Maybe a bot like onur said indexing all sites on that ip range?