At 02:40 AM 5/10/2000, Neil Schemenauer wrote:
>You should find the bottleneck before you jump to any
>conclusions. What version of the Linux kernel are you using?
2.2.12 compiled with higher process limit (4090), higher file and inode
limits (16000/48000), smp support, and drivers for SCSI and network card
compiled in.
>Do
>you have any strange looking error messages in your log files?
Nothing that looks unusual. A ton of "in.identd started" messages. No
unusual error messages.
>What does "vmstat 1" show?
I didn't know that one. I'll check when the servers are busy the next time.
Generally top shows relatively low memory use and no swap space used.
>Perhaps you should install sar(sp?)
>and profile your disk IO.
I don't think sar or sarcheck runs on Linux at this point, as far as I can
quickly figure out. But something like that would be very useful.
At 07:09 AM 5/10/2000, Ricardo D. Albano wrote:
>Are you using syslogd ?
No. Or, rather, it is there, but I'm not using it for qmail, so it is not
doing much. Back when I was using sendmail and syslogd, that was indeed a
big bottleneck, ending up consuming a majority of server resources.
At 10:09 AM 5/10/2000, [EMAIL PROTECTED] wrote:
>It's not clear to me that these are valid comparisons. Is the 12mill per day
>mean 12M individual messages individually queued? Are is it a much smaller
>number of messages with a larger number of recipients?
I'd like to know that too. What I'm doing is individual messages
individually queued, so if somebody can get 12M that way, I'm certainly
paying attention. I'd be perfectly happy doing 2M per machine without
crashing anything.
>While it's hard to tell without looking, my guess is that your inbound
>submission rate is killing the spindle that your disk lives on.
Sort of looks like it. I suppose there is no meaningful way of separating
the stuff I put in from what needs to go out, as it is obviously the same
queue.
And, still, I don't get it. I can't seem to feed much more than 60,000
messages per hour into the queue. That's between two machines standing next
to each other, on a 100Mbps switched network. SMTP or QMTP seems to make no
difference. That's no faster than the machine can go and deliver the
messages remotely, when it is in a good mood, and nothing is coming in at
the time.
I would be able to create 60,000 mail message files in a couple of minutes.
Should I be thinking along the lines of putting the files directly into the
queue myself? I'd really be much more comfortable leaving that kind of
stuff to qmail-qmtp and qmail-queue.
>In other words, expect to reach your concurrencyremote. Not getting their
>when everything appears right, is a sign of some other underlying problem.
Now, after saying all of this, I did get a hint yesterday that my outgoing
bottleneck might possibly relate to bandwidth problems. I was mailing from
3 machines at the same time, each with around 100,000 messages in the queue
and concurrencyremote set at 200. And for the first time I saw one of them
actually sneak up to 200, with ~3Mbps outgoing traffic, without even
working very hard. However, while the other two were idling around 20-30.
And a little later another of the machines went up towards 200, while the
first one dropped down to 20-30. Seemed kind of bizarre, but might indicate
some kind of "smart" network switch that's trying to apportion out
bandwidth according to some algorhitm. I'm looking into that.
- Flemming
