PERC3 performance issues

Alexander Lazarevich alazarev at hera.itg.uiuc.edu
Wed Dec 4 17:41:00 CST 2002


We've got:

PE4600
dual 2.8GHz
4GB ram
PERC3/QC RAID controller
10 X 73 GB Maxtor U320 drives
redhat linux 7.3
2.4.18-18.7.xsmp kernel
ext3 filesystems

if i configure a single maxtor drive in a RAID 0 configuration, put an
ext3 filesystem on it, and run some bonnie++ benchmarks, i get 30MB/sec
writes.

if i configure 8 drives in a RAID 5 configuration on the same exact
RAID channel (destroy the RAID 0 first), and setup an ext3 filesystem of
the same size, and run the same exact bonnie++ benchmark, i get 46MB/sec
write.

that seems bad. if a single disk can do 30MB/sec, then shouldn't 8 drives
in a RAID 5 be able to do about 140MB/sec writes? everything is the same
except the RAID configuration and number of disks.

anyone have similar problems/complaints?

thanks!

alex
---                                                        ---
   Alex Lazarevich | Systems | Imaging Technology Group
   alazarev at itg.uiuc.edu | (217)244-1565 | www.itg.uiuc.edu
---                                                        ---





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