Re: Parameters for PostgreSQL

On 04/08/11 11:42, Jayadevan M wrote:
> Hello,
>
> >The most important spec has been omitted. What's the storage subsystem?
> We have storage on SAN, RAID 5.

RAID 5? That's *really* not ideal for database workloads, either Pg or
Oracle, unless your RAID 5 storage backend has enough battery-backed
write cache to keep huge amounts of writes in RAM and reorder them
really effectively.

I hope each RAID 5 LUN is only across a few disks and is layered with
RAID 1, though. RAID 5 becomes less reliable than using a single disk
when used with too many HDDs, because the probability of a double-disk
failure becomes greater than that of a single standalone disk failing.
After being bitten by that a few times, these days I'm using RAID 6 in
most cases where RAID 10 isn't practical.

In any case, "SAN" can be anything from a Linux box running an iSCSI
target on top of a RAID 5 `md' software RAID volume on four 5400RPM
HDDs, right up to a giant hundreds-of-fast-disks monster filer full of
dedicated ASICs and great gobs of battery backed write cache DRAM. Are
you able to be any more specific about what you're dealing with?

>
> > > We are suing weblogic.
> > ^^^^^
> > Best. Typo. Ever.
> >
> > I hear most people who use it want to, you're just brave enough to
> do it :-P
> I wish I could make a few millions that way.
>
>
> Thank you for all the replies. The first step is, of course, to
> migrate the data. I am working with ora2pg for that. I assume creating
> files with 'COPY' to work as input for PostgreSQL is the right
> approach? We don't have many stored procedures or packages. So that
> part should be OK.