Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Capacities up to 48TB and speeds up to 1527MB/s

Atto/iStoragePro Test Results for RAID-6 Striping + Dual Parity

Last updated 2010-11-07 - Send Feedback
Related: Storage, storage, RAID

iStoragePro with Atto R380 using Oct 26 2010 firmware

RAID-6 scalability is near-linear through 8 drives for reads, but flatlines at 7 drives for writes. This performance is consistent with the RAID-5 results and RAID-0 results .

As one might hope, RAID-6 with its two parity drives achieves performance very similar to RAID-0 with 2 more drives. In other words, 8 drives for RAID-6 is about as fast as 6 drives for RAID-0, though it could be somewhat less as the same amount of data is added.

Since RAID-0 is seen to be non-scalable past 6 drives, from a reliability perspective, an 8-drive RAID-6 configuration is a far better choice for its resilience: up to two drive failures can be tolerated.

Scalability of RAID-6 striping + dual parity with 4...8 drives

Speed compared to RAID-5

The results of a DiskTester fill-volume test are shown below.

Here, the RAID-5 results are using 7 drives plus a hot spare, so the same total capacity is at play( (12GB).

The Atto R380 card throttles RAID-5 write performance to about 635 MB/sec. Oddly, RAID-6 writes are slightly faster than RAID-5 writes, which are throttled to about 655MB/sec. Faster performance with two parity drives is unexpected.

Since hard drives vary in speed over the area of the drive, the flatlined write performance continues until the drive speed declines below the throttling effect.

Click for a full-size graph.

DiskTester fill-volume
MB/sec filling the entire drive, then reading the files
Durable and fast, up to 1800MB/s
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 7 hours unless noted. Certain deals may last longer.
$1199 SAVE $500 = 29.0% $19 FREE ITEMS Canon 18x50 IS Image Stabilized Binocular in All Other Categories
$1049 SAVE $450 = 30.0% $20 FREE ITEMS Canon EOS 77D DSLR with 18-135mm USM in Cameras: DSLR
$1697 SAVE $300 = 15.0% Nikon D750 DSLR in Cameras: DSLR
$2797 SAVE $200 = 6.0% Nikon D810 DSLR in Cameras: DSLR
$898 SAVE $100 = 10.0% Sony DSC-RX100 V in Cameras: Point and Shoot
$300 SAVE $160 = 34.0% $9 FREE ITEMS Steiner 8x32 XC Binocular in All Other Categories
$1099 SAVE $200 = 15.0% ZEISS 25mm f/2 Batis in Lenses: Mirrorless
$1299 SAVE $200 = 13.0% ZEISS 21mm f/2.8 Loxia in Lenses: Mirrorless
$1999 SAVE $300 = 13.0% ZEISS 18mm f/2.8 Milvus ZF.2 in Lenses: DSLR

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2008-2017 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__