Re: Indexes on ramdisk

Talk about your IO system a bit. There might be obvious ways to improve.

What System/Motherboard are you using?
What Controller Cards are you using?
What kind of Disks do you have (SATA, SCSI 7.6k 10k 15k)
What denominations (9, 18, 36, 72, 143, 80, 160, 200 240Gig)?
What kind of RAIDs do you have setup (How many drives what stripe sizes, how
many used for what).
What levels of RAID are you using (0,1,10,5,50)?

With good setup, a dual PCI-X bus motherboard can hit 2GB/sec and thousands
of transactions to disk if you have a controller/disks that can keep up.
That is typicaly enough for most people without resorting to SSD.

Alex Turner
NetEconomist

On 10/4/05, Emil Briggs <emil(at)baymountain(dot)com> wrote:
>
>
> I have an application that has a table that is both read and write
> intensive.
> Data from iostat indicates that the write speed of the system is the
> factor
> that is limiting performance. The table has around 20 columns and most of
> the
> columns are indexed. The data and the indices for the table are
> distributed
> over several mirrored disk partitions and pg_xlog is on another. I'm
> looking
> at ways to improve performance and besides the obvious one of getting an
> SSD
> I thought about putting the indices on a ramdisk. That means that after a
> power failure or shutdown I would have to recreate them but that is
> acceptable for this application. What I am wondering though is whether or
> not
> I would see much performance benefit and if there would be any startup
> problems after a power down event due to the indices not being present.
> Any
> insight would be appreciated.
>
> Emil
>
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