I've recently noticed slow performance on a machine that runs amanda and stores
backups for our network on a RAID-5. It was running 6.2. I upgraded to 6.3 just
today, so it is completely up to date on the 6 branch. Here's hopefully most of the
relevant info:
6.3-STABLE FreeBSD 6.3-STABLE #0: M
This is a very important point. By turning the cache on, you have not
resolved an underlying performance issue, if there even is one. Please
try dd again with a well-sized bs= parameter, or use some more
accurate reporting like iozone, sysbench, etc.
Also, I am not sure how much memory is on the c
On Jun 9, 2008, at 2:09 PM, Adam Bayless wrote:
[ ... ]
Unit UnitType Status %Cmpl Stripe Size(GB) Cache
AVerify IgnECC
--
u0RAID-5OK - 64K 2095.44 OFF
OFF OFF
C
Caching is off; that will kill performance especially for small
transactions. If you've got battery backup for this system, consider
enabling the onboard cache...?
Chuck, that made an immediate and huge difference:
# tw_cli set cache c0 u0 on
# dd if=/dev/zero of=testfile
5649235+0 r
On Jun 9, 2008, at 3:09 PM, Adam Bayless wrote:
Caching is off; that will kill performance especially for small
transactions. If you've got battery backup for this system,
consider enabling the onboard cache...?
Chuck, that made an immediate and huge difference:
# tw_cli set cache c0 u0
dd if=/dev/zero of=testfile
165760+0 records in
165759+0 records out
84868608 bytes transferred in 25.028232 secs (3390915 bytes/sec)
I think I ought to be able to get more than 3.2MB/sec out of this card,
with default 512 bytes blocks - not much more
_
