RC8- parity check speed just 60% of RC4

[fitbrit]

I just installed RC8, and noticed that parity check speed is a painful 25 MBps compared with the 40 MBps of RC4. Anyone else seeing this?

[limetech]

What's your h/w config?  I consistently see 60-70MB/sec with 10 drives: 8 on AOC-SASLP-MV8, 2 on Intel ICH9R controller.

[Marky]

I've not tried RC8 yet to see if speed problems are still there but all RC releases i've tried have the problem.

 

4.7 parity check ~55MB/s

B14 parity check ~50MB/s (stilll using this version due to speed issues on RC's)

 

RC? parity check ~17MB/s!!!!!

 

Here's the hardware config.

 

20 Hitachi drives

Supermicro C2SEA Motherboard

2x AOC-SASLP-MV8 Controllers

 

4 drives on the motherboard (1 of which is the parity) and the other 16 on the 2 SASLP controllers

 

Mark

 

[fitbrit]

Sorry, was away for a few days. Hardware: Norco 4224.

20 data drives, now mostly Hitachi 2 TB Green, some 1.5 TB WD Greens (EADS). Parity is a 2TB WD Black

Asus P5Q Premium motherboard

2x AOC-SASLP-MV8 Controllers

 

Parity, plus drives 1-9 are on mobo, the rest on the PCIex4 controllers.

[tyrindor]

I've been reporting this for awhile. b12 for me is ~100MB/s, pretty much everything after is ~65MB/s and only gets slower. 28 hours to sync 3TB parity, which is a bit too much considering my server with PCI-X cards (much slower) manages ~85MB/s with the latest RC. I'd also like to note that if I invalidate my parity and do a fresh rebuild, I get ~100MB/s, it's only related to actual parity syncs.

 

I have 2 servers with SAS2LP cards, and they both do it. There is definitely a pattern emerging that it is related to SASLP/SAS2LP cards.

[WeeboTech]

Is the parity on the motherboard controller or SASLP controller?

I've found that parity create/generate is faster then parity check/sync.

 

 

[fitbrit]

Is the parity on the motherboard controller or SASLP controller?

I've found that parity create/generate is faster then parity check/sync.

 

My parity drive is on the motherboard, which is what I believed is the best way to do it.

[WeeboTech]

Is the parity on the motherboard controller or SASLP controller?

I've found that parity create/generate is faster then parity check/sync.

 

My parity drive is on the motherboard, which is what I believed is the best way to do it.

 

For some configurations yes. but if your motherboard has a bandwidth of 384Kb/s and you have 5 other data drives on the same chipset, there will be competition.  I suppose you could move the parity drive to another controller and see how your speeds change.

 

This was one of the reasons I elected to use the ARC-1200 on a PCIe X1 slot. The parity drive always gets full bandwidth without competition.

[fitbrit]

Thanks for the advice. I might try that eventually. I have a decent WD Black drive as parity and it would be a shame to choke it. However, the fact remains that the parity check speed is slower in RC8, with the same config as I currently have, compared to RC4.

 

[PattayaPete]

I recently upgraded to RC8

 

I've just replaced my parity drive upgrading from 2 to 3 tb.  Started building the new sync yesterday and was getting speeds of 35MB.  I used to get 65MB on 4.7.  It's still running some 26 hours later and has slowed to 23 MB and showing 343 minutes to run, 84% complete.

 

My system has 10 data drives all 2tb wd green.  The new parity is a 3tb western green.  All data drives have spun down now as there is no data after 2 TB.

 

This does seem incredibly slow.

[downloadski]

My last parity check claimed to have an average of 68 MByte/sec. I have a mix of discs, and seen large difference on which type of hdd it is running. up till 1 TB is the slowest (30-40 Mbyte/sec) than slightly faster from 1 TB to 1.5 TB, again slightly faster for 1.5 - 2.0 TB and above than i get the 80+ Mbyte/sec

All the data drives are on SAS2LP cards, parity is on mainbord.