Software RAID5 under Linux

[Headcase_Fargone]

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]

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]

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.

 

[dustNbone]

Agree. i've found mdadm very efficient at parity, it's hard to beat the cost of commodity processing power.

 

[Headcase_Fargone]

Good deal. Thanks guys.