| From: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz> |
|---|---|
| To: | Andrew Sullivan <andrew(at)libertyrms(dot)info> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Recomended FS |
| Date: | 2003-10-22 08:57:08 |
| Message-ID: | 3F964664.80303@paradise.net.nz |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
I have found this as well -
I have a nice simple example of a program that loops and occasionally
writes a block to a file.
On a 2 cpu machine, running 2 of these processes in parallel takes twice
as long as running just 1 process!
However if I comment out the IO, then 2 processes takes the same elapsed
time as 1.
My conclusion is there exists some sort of "big" lock on access to the
ATA array.
I believe that 3ware have a non blocking implementation of ATA RAID -
I intend to sell the Promise and obtain a 3ware in the next month of so
and test this out.
regards
Mark
Andrew Sullivan wrote:
>That said, even the 2-way RAID became almost uselessly slow when
>multiple queries were running -- indeed, dramatically slower than a
>plain single IDE drive.
>
>
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