Re: High load average in 64-core server , no I/O wait and CPU is idle

----- "Stephen Frost" <sfrost(at)snowman(dot)net> wrote:

| From: "Stephen Frost" <sfrost(at)snowman(dot)net>
| To: "Rajesh Kumar. Mallah" <mallah(at)tradeindia(dot)com>
| Cc: pgsql-performance(at)postgresql(dot)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(at)tradeindia(dot)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