Subject: [linux-audio-dev] theoretical 100 tracks @ 24bit on a Linux SOFTWARE RAID5 SCSI box :-)
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Fri Apr 21 2000 - 18:08:41 EEST
Hi,
I made a few tests with hdtest.c in order to evaulate the performance of
a server of a friend of mine , Udo Jocher (udo_AT_udoj.org).
The box is a dual PIII 450 with 512MB RAM and a software RAID5 array consisting
of 5 9GB Quantum Atlas IV9 SCA UW2 SCSI disks.
I tried hdtest and increased the number of files to 100.
I get about 26MB/sec sustained during the single threaded test.
Now with a 48Khz @ 32bit track having a datarate of about 200KB/sec,
that means more than 100 tracks simultaneously.
I have yet to deterimine how much buffersize you would need in order to overcome
to filesystem latencies, but it would be definitively possible to get 100
tracks sustained. (when I get some time I will port hdrbench to audio-less
architectures, with an output module which doesn't output audio but simulates
the datarate by throttling down the speed to 180-200KB/sec)
Plus consider the fact that you are running on a RAID5 array, that means 100%
data saefty even if a disk breaks (although the disk performance might suffer
a bitdue when running in degraded mode).
(the cost of the box is about $7-8k, I believe. Notice that the disk
performance is about 60% better than on the SGI O2k which costed 10-20 times
more :-) )
add a couple of Hammerfalls and you get the DAW of your dreams.
(And if it's not enough for you we can always cluster :-) )
I can only say kudos to the linux-raid folks !
Benno.
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