[mythtv-users] OT Hardware RAID 5 Recommendations

Paul Hamm paulhamm at verizon.net
Tue Dec 12 22:31:41 UTC 2006


> Here's the very best part... I could have left those benchmarks
> running for 60 minutes straight (done it as a test) and I would not
> have dropped a video frame, chugged out a recording, or caused any
> instability in the box. The HW Raid card (true HW Raid, not psuedo
> rocket cards) was worth every penny.

Totally agree with you on the HW raid vs software raid.  Much more
consistent, much more reliable.

Tried bonnie++

[root at bigboy temp]# bonnie++ -d /vault/01/home/temp -u0 -g0 -n0 -s 8192
Using uid:0, gid:0.
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Version  1.03       ------Sequential Output------ --Sequential Input-
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %
CP  /sec %CP
blah.blah      8G 35780 65 58065 22 41983 11 59912 91 209615 21 243 0 1



After the first tests I realized that the system ram was likely causing
the suspect variation on performance.  Ran with a bigger file.  dd seems
to use 20-30% of one CPU core while running.  

[root at blah temp]# time dd if=/dev/zero of=test bs=1M count=8192
8192+0 records in
8192+0 records out
8589934592 bytes (8.6 GB) copied, 150.142 seconds, 57.2 MB/s

real    2m30.173s
user    0m0.033s
sys     0m34.435s
[root at blah temp]# time rm -f test
[root at blah temp]# time dd if=/dev/zero of=test bs=1M count=8192
8192+0 records in
8192+0 records out
8589934592 bytes (8.6 GB) copied, 154.153 seconds, 55.7 MB/s

real    2m34.187s
user    0m0.020s
sys     0m35.221s
[root at blah temp]# time rm -f test

real    0m10.577s
user    0m0.000s
sys     0m0.951s
[root at blah temp]# time dd if=/dev/zero of=test bs=1M count=40960
40960+0 records in
40960+0 records out
42949672960 bytes (43 GB) copied, 758.55 seconds, 56.6 MB/s

real    12m38.614s
user    0m0.120s
sys     2m47.640s
[root at blah temp]# time rm -f test

real    1m5.376s
user    0m0.001s
sys     0m3.809s
[root at blah temp]# time dd if=/dev/zero of=test bs=1M count=40960
40960+0 records in
40960+0 records out
42949672960 bytes (43 GB) copied, 786.659 seconds, 54.6 MB/s

real    13m6.697s
user    0m0.124s
sys     3m3.311s
[root at blah temp]# time rm -f test

real    1m6.168s
user    0m0.000s
sys     0m3.609s



-- 
Paul Hamm




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