From: Tim Chipman (chipman@ecopiabio.com)
Date: Tue Jul 22 2003 - 14:46:04 EDT
Hi all,
In light of one response I got to my summary, as well as a bit of
testing done since that time, I thought I should recap with a bit more
info, to be more fair/accurate.
My posting was regarding problems of poor performance observed when
accessing (cp, ftp, netbackup) a large (130gig) file on an external
raid5 disk brick connected to a sol8X86 box via an adaptec U160 SCSI HBA
; such problems were NOT observed when identical file access was
performed against a "small" (50 gig) file on the same system.
-> In my original summary, I whinged and moaned that "Sun ought to do
something about the cadp160 driver". In fact, it is true that Sun can't
do anything about this driver, since it is written & maintained by
Adaptec. If, of course, sun felt like writing a replacement driver to
usurp the function of cadp160, I wouldn't be unhappy, but I'm not
holding my breath :-) [in fact, it was pointed out to me that based on
my experience so far, there is no conclusive proof that cadp160 is the
cause of my problems - which is true ; it is just one suspect on my list
of candidates].
-> Since posting the summary, I upgraded the cadp160 driver from version
1.1.0 as bundled with solaris8X86 10/03 to the newest available driver
(version 1.2.1, as downloaded from adaptec's website.) Performance for
the "before" vs "after" for cp,ftp,netbackup are summarized:
Performance of "cp between-2-slices-on-disk-array" for
driver used 130gig file 50gig file
==============================================================
cadp160 driver v.1.1.0 1.47mb/sec 4.7mb/sec
cadp160 driver v.1.2.1 2.51mb/sec 4.7mb/sec
(note that nothing else changed other than the cadp160 driver version)
These ##'s suggest performance is still significantly slower for the
same action against this large vs. small file ; however the driver
update did appear to have some impact on performance.
Further testing (still pending) is to swap in a different (Ultra40
adaptec HBA, which would use cadp as the driver (ie, a totally different
driver that was written by Sun, I believe) -- and see if any difference
in performance persists with manipulation of the large vs small file.
For the moment, however, I've deleted this monster file and will
probably leave further testing on the back burner, since we infrequently
create such large files. The primary concern was that it represented a
larger underlying problem that could result in other (more severe) problems.
as an aside: deleting the 130 gig file took ~10 minutes, and for the
duration of the process, the system was effectively "hung". In contrast,
deleting the 50 gig file was effectively instantaneous and had no impact
on system responsiveness. Not sure if anyone else has seen this
behaviour or not ever. Great fun.
Finally: as recommended by one respondant to my summary, I did submit a
problem report to adaptec, who assure me that nobody has ever had this
kind of problem. Yay.
So. Hope this info is of slight interest to someone, if not now then
maybe in the future.
Thanks,
--Tim Chipman
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