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My server regularly falls over. I'm on a vps package that is supposed to support 600 online users. It has 1.1m posts and normally around 100 users.
Slow query log suggests search is the problem (normally a search query is the first one to go slow e.g. 200+ just before the server goes mental with 100+ load....)
It's v4.1.5 and I run with very few basic plugins and all the intensive options in vb are turned off out of necessity.
I have had the search facility on the forum turned off since yesterday.
This has allowed me to see if anything else is causing the problem or if it's just intensive search.
I have taken a couple of screenshots from "top" (see attached)
The first one is just normal forum activity, albeit seeming a bit slow - see attachment "Top(withSearchTurnedOff).gif"
In this shot you can see that cpu is barely registering but "wait" (disc access) is maxed out.
Later at the start of typing this message, I had a look and wait is similarly high (would make a similar screenshot).
At the end of typing this message, wait had dropped off (but still jumps around between 0 and 50%)
That's not good is it?
The next one called "Top(Delete6LargestAttachments).gif" shows an attempt to delete 6 attachments via vbulletin's admin panel.
Firstly in vbulletin admin: "View largest attachments" - this takes 10 seconds to show 10 attachments. Again the cpu is doing nothing and wait is maxed. (There are 4000 attachments to search through - not that many I think).
Then of the top 10, I selected 6 and asked it to delete them. I would have thought that this would have been a fairly quick task - delete 6 files and send 6 updates to the database accordingly (the attachments are stored in the filesystem, not the database by the way).
However it took around 20 seconds. This is repeatable.
Again, the CPU is doing very little and the everything is just waiting for the disc.
I'd expect the answer here would be "hosts fault", but perhaps someone has a suggestion for something I can check to confirm where the issue might stem from (e.g. I/O problems or vbulletin/database problems).
Thanks!
Finally in the past hour, even with search turned off, I've had 10 queries appear in the slow query log.
For example
# Time: 110901 12:40:52
# Query_time: 24 Lock_time: 0 Rows_sent: 1 Rows_examined: 14191
SELECT post.postid
FROM post AS post
WHERE post.threadid = 34853
AND post.visible = 1
AND post.userid NOT IN (3472,11,4180)
ORDER BY post.dateline
LIMIT 14190, 10;
Is this a normal amount of queries to be appearing in the slow query log? The queries don't seem to be very exciting.
Slow query log suggests search is the problem (normally a search query is the first one to go slow e.g. 200+ just before the server goes mental with 100+ load....)
It's v4.1.5 and I run with very few basic plugins and all the intensive options in vb are turned off out of necessity.
I have had the search facility on the forum turned off since yesterday.
This has allowed me to see if anything else is causing the problem or if it's just intensive search.
I have taken a couple of screenshots from "top" (see attached)
The first one is just normal forum activity, albeit seeming a bit slow - see attachment "Top(withSearchTurnedOff).gif"
In this shot you can see that cpu is barely registering but "wait" (disc access) is maxed out.
Later at the start of typing this message, I had a look and wait is similarly high (would make a similar screenshot).
At the end of typing this message, wait had dropped off (but still jumps around between 0 and 50%)
That's not good is it?
The next one called "Top(Delete6LargestAttachments).gif" shows an attempt to delete 6 attachments via vbulletin's admin panel.
Firstly in vbulletin admin: "View largest attachments" - this takes 10 seconds to show 10 attachments. Again the cpu is doing nothing and wait is maxed. (There are 4000 attachments to search through - not that many I think).
Then of the top 10, I selected 6 and asked it to delete them. I would have thought that this would have been a fairly quick task - delete 6 files and send 6 updates to the database accordingly (the attachments are stored in the filesystem, not the database by the way).
However it took around 20 seconds. This is repeatable.
Again, the CPU is doing very little and the everything is just waiting for the disc.
I'd expect the answer here would be "hosts fault", but perhaps someone has a suggestion for something I can check to confirm where the issue might stem from (e.g. I/O problems or vbulletin/database problems).
Thanks!
Finally in the past hour, even with search turned off, I've had 10 queries appear in the slow query log.
For example
# Time: 110901 12:40:52
# Query_time: 24 Lock_time: 0 Rows_sent: 1 Rows_examined: 14191
SELECT post.postid
FROM post AS post
WHERE post.threadid = 34853
AND post.visible = 1
AND post.userid NOT IN (3472,11,4180)
ORDER BY post.dateline
LIMIT 14190, 10;
Is this a normal amount of queries to be appearing in the slow query log? The queries don't seem to be very exciting.
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