RAID performance problems
sehh at altered.com
Fri Jan 24 18:37:13 GMT 2003
Hello, i'm using a DELL PowerEdge Expandable RAID controler (PERC 3/DCL,
which is the LSI MegaRAID Elite 1600).
The card is 64bit/66mhz, and its installed in my dual athlon board
(Asus A7M266-D) on one of the 64bit/66mhz slots. All other slots are empty.
The problem is that i get very slow writes. Writes are at 20meg/s and
reads are at 150meg/s. (writes should easily reach 80meg/s)
The system runs two IBM Ultrastar 73LZX 10k rpm 18gig drives as RAID 0 (64k stripe).
The problem first appeared under FreeBSD 5.0-R (haven't tried older versions),
but i installed WindowsXP just in case the problem was specific to fbsd, but
then i got the same performance problem.
The logical array runs with Direct I/O enabled, WriteThrough enabled, and Adaptive read ahead.
Anyone seen similar problems? Suggestions are welcome :)
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