markwkm at gmail.com
Wed May 6 15:01:30 UTC 2009
On Wed, May 6, 2009 at 2:25 AM, Anthony Pankov <ap00 at mail.ru> wrote:
> Hello Mark,
> May i ask a question while more expierenced people is waking up?
> I don't fully understand the target. For what filesystem should be
> I expect a patterns of recorded IO calls when pgsql perform typical
> operations with statistics and in-depth analysis.
The angle we're trying to look at is from a sizing perspective. In
order words we want to have an idea of what to expect before we do it.
For example, if I have 10 drives, what can I expect if I configure
them in a RAID 10 configuration?
> Are you sure there is ą strong relation between fio benchmark result and
> PostgreSQL performance?
Sorry, this was something I was trying to make clearer originally.
No, I don't think there is a strong relationship between fio and
PostgreSQL, but these i/o patterns we are simulating do give us a
rough estimate of we can expect. For example, in workloads with lots
of update and inserts into a database will generate a lot of
sequential writes to the database logs, which we can physically
isolate onto it's own lun. Similarly, in some warehousing
applications there may be a table that is always scanned and read
sequential, which also can be on its own physical lun.
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