Re: disk performance benchmarks - Mailing list pgsql-general

From Jeffrey W. Baker
Subject Re: disk performance benchmarks
Date
Msg-id 1095202131.7232.2.camel@localhost.localdomain
Whole thread Raw
In response to Re: disk performance benchmarks  ("Jim C. Nasby" <decibel@decibel.org>)
List pgsql-general
On Tue, 2004-09-14 at 14:45, Jim C. Nasby wrote:
> On Tue, Sep 14, 2004 at 11:11:38AM -0700, Jeffrey W. Baker wrote:
> > procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
> >  r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
> >  3  0    216  13852  39656 7739724    0    0   820  2664 2868  2557 16  2 74  7
> >  0  0    216  17580  39656 7736460    0    0  3024  4700 3458  4313 42  6 52  0
> >  0  0    216  16428  39676 7737324    0    0   840  4248 3930  4516  0  4 89  8
> >  0  1    216  18620  39672 7736920    0    0  7576   516 2738  3347  1  4 55 39
> >  0  0    216  14972  39672 7738960    0    0  1992  2532 2509  2288  2  3 93  3
> >  0  0    216  13564  39672 7740592    0    0  1640  2656 2581  2066  1  3 97  0
> >  0  0    216  12028  39672 7742292    0    0  1688  3576 2072  1626  1  2 96  0
> >  0  0    216  18364  39680 7736164    0    0  1804  3372 1836  1379  1  4 96  0
> >  0  0    216  16828  39684 7737588    0    0  1432  2756 2256  1720  1  3 94  2
> >  0  0    216  15452  39684 7738812    0    0  1188  2184 2384  1830  1  2 97  0
> >  0  1    216  15388  39684 7740104    0    0  1336  2628 2490  1974  2  3 94  2
> >  6  0    216  15424  39684 7740240    0    0   104  3472 2757  1940  3  2 92  2
> >  0  0    216  14784  39700 7741856    0    0  1668  3320 2718  2332  0  3 97  0
> >
> > You can see there's not much progress being made there.   In the
>
> Those IO numbers look pretty high for nothing going on. Are you sure
> you're not IO bound?

Just for the list to get an idea of the kinds of performance problems
I'm trying to eliminate, check out these vmstat captures:

http://saturn5.com/~jwb/pg.html

Performance is okay-ish for about three minutes at a stretch and then
extremely bad during the fourth minute, and the cycle repeats all day.
During the bad periods everything involving the database just blocks.

-jwb

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