Software RAID5 under Linux

Headcase_Fargone

Limp Gawd
Joined
Mar 25, 2010
Messages
284
I'm planning to build a new tiny media server around a Zacate E-350 board with six SATA ports. I had hoped to run a RAID5 setup under Ubuntu using mdadm, but someone on an HTPC forum mentioned that I could only expect 10-15MBps write speeds to this array. Is this true?

I knew performance wouldn't be stellar using software RAID on such a puny CPU, but that seems awfully low. Can anyone here that might be running a similar setup give me some idea what sort of performance I can expect?
 

TheMTZ

Limp Gawd
Joined
Jan 17, 2011
Messages
189
I had a software raid on Linux with 3x 1 TB WD green drives on a Intel Atom 230 (single core with HT on) and write speed was like 130 MB/sec - which would have been slightly better with a faster CPU - but still good enough imo.
 

drescherjm

[H]F Junkie
Joined
Nov 19, 2008
Messages
14,937
I had hoped to run a RAID5 setup under Ubuntu using mdadm, but someone on an HTPC forum mentioned that I could only expect 10-15MBps write speeds to this array. Is this true?

Absolutely not. I would expect 200 to 300 MB/s STR. If you tune the array. Hint increase stripe_cache_size from 256 to 4096 or 8192.

I knew performance wouldn't be stellar using software RAID on such a puny CPU

Remember that your puny CPU is faster at calculating XOR than the CPU on most HW raid cards.
 
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dustNbone

[H]ard|Gawd
Joined
Apr 7, 2009
Messages
1,032
Agree. i've found mdadm very efficient at parity, it's hard to beat the cost of commodity processing power.
 
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