A quick call to 3ware and they told me to increase vfs.read_max from
8 to 256. That helped. I'm now seeing 4x performance on a four-drive
array vs a single drive. Additionally, Ivan was right about the
database being too small. iostat showed no disk activity after the
initial run, as everyt
Milo Hyson wrote:
> I also ran some performance tests with a stock build of PostgreSQL 8.0
> to get a different angle on things. Two tests were run on each of the
> UDMA system drive, the RAID 5 unit, and the RAID 10 unit. The first
> tested sequential-scans through a 58,000+ record table. The sec
On Jan 25, 2007, at 13:50, Jeff Mohler wrote:
How about one large raid, and two partitions to serve each purpose?
Being so limited in HW, youre either going to take a _huge_
performance hit with only 2 disks per raid (unless Raid0), or an
availability hit with everything on one RAID set.
How about one large raid, and two partitions to serve each purpose?
Being so limited in HW, youre either going to take a _huge_
performance hit with only 2 disks per raid (unless Raid0), or an
availability hit with everything on one RAID set.
But..considering the costs of adding RAID to a se
On Jan 25, 2007, at 12:15, Chuck Swiger wrote:
Still, you also ought to consider that a 3-disk RAID-5
configuration is very much not ideal from either an efficiency or
performance standpoint-- you want more like 5 or 6 drives being
used, in which case your performance numbers ought to incre
On Jan 25, 2007, at 10:50 AM, Milo Hyson wrote:
The write times of both RAID configurations are slower than the
single drive (which is expected due to having to write to multiple
drives). However, I wasn't expecting such a drastic reduction
(about 50%). The read times, although faster, are o
Milo
if you hunt around you should see papers/articles where it shows foe RAID 5
you need at least 5 drives before you any dramatic performance gains..(sun
old Sun articles from around 1998 where they do the math as well).
not sure about RAID 10, but again I *think* you need at least 3 drives in
I don't really have a whole lot of experience with RAID, so I was
wondering if the performance figures I'm seeing are normal or if I
just need to tweak things a bit. Based on what I've been reading, I
would expect more significant improvements over a single drive.
Here's my setup:
* FreeB
