From: Rajesh Kumar. Mallah <mallah@tradeindia.com>
To: Stephen Frost <sfrost@snowman.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: High load average in 64-core server , no I/O wait and CPU is idle
Date: Thu, 24 May 2012 22:29:55 +0530 (IST)
Message-ID: <8120287.465321337878795023.JavaMail.root@zmbox01.trade-india-local.com> (raw)
In-Reply-To: <20120524155737.GP1267@tamriel.snowman.net>
----- "Stephen Frost" <sfrost@snowman.net> wrote:
| From: "Stephen Frost" <sfrost@snowman.net>
| To: "Rajesh Kumar. Mallah" <mallah@tradeindia.com>
| Cc: pgsql-performance@postgresql.org
| Sent: Thursday, May 24, 2012 9:27:37 PM
| Subject: Re: [PERFORM] High load average in 64-core server , no I/O wait and CPU is idle
|
| Rajesh,
|
| * Rajesh Kumar. Mallah (mallah@tradeindia.com) wrote:
| > We are puzzled why the CPU and DISK I/O system are not being
| utilized
| > fully and would seek lists' wisdom on that.
|
| What OS is this? What kernel version?
Dear Frost ,
We are running linux with kernel 3.2.X
(which has the lseek improvements)
|
| > just a thought, will it be a good idea to partition the host
| hardware
| > to 4 equal virtual environments , ie 1 for master (r/w) and 3
| slaves r/o
| > and distribute the r/o load on the 3 slaves ?
|
| Actually, it might help with 9.1, if you're really running into some
| scalability issues in our locking area.. You might review this:
|
| http://rhaas.blogspot.com/2012/04/did-i-say-32-cores-how-about-64.html
|
| That's a pretty contrived test case, but I suppose it's possible your
| case is actually close enough to be getting affected also..
Thanks for the reference , even i thought so (LockManager) ,
but we are actually also running out db max connections (also)
( which is currently at 600) , when that happens something at
the beginning of the application stack also gets dysfunctional and it
changes the very input to the system. ( think of negative feedback systems )
It is sort of complicated but i will definitely update list ,
when i get to the point of putting the blame on DB :-) .
Regds
Mallah.
|
| Thanks,
|
| Stephen
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Cc: mallah@tradeindia.com, sfrost@snowman.net
Subject: Re: High load average in 64-core server , no I/O wait and CPU is idle
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