RAID5 vs RAID10 speed - GoFuckYourself.com

rowan · 03-02-2007, 03:11 PM

I migrated my array from RAID10 to RAID5, and ran HD tach on each...

RAID10: Average read 93.6MB/s, burst 214.7MB/s
RAID5: Average read 163.0MB/s, burst 1143.3MB/s

I'm sceptical of the burst speed for RAID5. Can the data/RAM bus even transfer data at 1143 megs per sec?

I also expected average read for RAID5 would be similar, or perhaps even worse than RAID10.

My comp just rebooted, now I remember why I changed from RAID5 to RAID10 all those months ago. The array is now rebuilding parity which means I have a slow as shit computer for the next 6 hours! If it reboots again then it's possible I'll lose the array.

Intel's RAID5 driver seems to be buggy as hell; never had a single problem on RAID10.

I guess I'll be reinstalling Windows today, the RAID10-RAID5 migration feature is one way only...

Snake Doctor · 03-02-2007, 03:14 PM

Is this like that teaspoon/tablespoon question that fucked me up on "Are you smarter than a 5th grader?" last night?

rowan · 03-02-2007, 03:33 PM

I rambled on a bit but basically I'm asking if those figures are plausible.

I guess it doesn't really matter since the array will be back to RAID10 later today.

rowan · 03-03-2007, 01:15 AM

bump5678

PHP-CODER-FOR-HIRE · 03-03-2007, 01:24 AM

Doesn't really matter.... no frequently accessed file is that big anyways. Look in your manual or on Google for stats on your hardware. I'm sure something else is the bottleneck anyways.

Also, don't forget that those are optimal figures. Sure, usb2.0 is supposed to do 480mbps, but it doesn't do it for very long.

rowan · 03-04-2007, 05:22 AM

I ended up having to reinstall Windows twice, realising at the worst possible time that I hadn't backed up the system state. All the executable and config files for my applications have been restored, but Windows itself doesn't know they exist. I've now restored my data only, time to manually reinstall 30 applications.....

rowan · 03-04-2007, 05:23 AM

Quote:

Originally Posted by PHP-CODER-FOR-HIRE

Doesn't really matter.... no frequently accessed file is that big anyways. Look in your manual or on Google for stats on your hardware. I'm sure something else is the bottleneck anyways.

Also, don't forget that those are optimal figures. Sure, usb2.0 is supposed to do 480mbps, but it doesn't do it for very long.

I do video capturing and also work with some pretty large image files (sometimes several hundred megs in size)

HD Tach measures the speed, so those numbers are what it has reported - it's not merely a spec...

rowan · 03-04-2007, 05:35 AM

1143 megabytes per sec is over 9 gigabits per second...

Interesting that this is apparently achievable when the drives are gen 1 (1.5Gbps), so the total maximum theoretical throughput of 4 drives is only 6Gbps.

Brad Mitchell · 03-04-2007, 07:49 AM

What type of drives were they, ide, scsi, SATA 150 , SATA 3.0 or SAS?

Also, what RAID controller?

Brad

rowan · 03-04-2007, 05:25 PM

Quote:

Originally Posted by Brad Mitchell

What type of drives were they, ide, scsi, SATA 150 , SATA 3.0 or SAS?

Also, what RAID controller?

SATA gen 1, Intel RAID (software) running under XP

That's pretty much why I doubted the figures were true... plus the fact that the bandwidth of the 4 SATA 1 channels don't add up to what HD Tach was reporting...

03-02-2007, 03:11 PM	#1
rowan Too lazy to set a custom title Join Date: Mar 2002 Location: Australia Posts: 17,393	RAID5 vs RAID10 speed I migrated my array from RAID10 to RAID5, and ran HD tach on each... RAID10: Average read 93.6MB/s, burst 214.7MB/s RAID5: Average read 163.0MB/s, burst 1143.3MB/s I'm sceptical of the burst speed for RAID5. Can the data/RAM bus even transfer data at 1143 megs per sec? I also expected average read for RAID5 would be similar, or perhaps even worse than RAID10. My comp just rebooted, now I remember why I changed from RAID5 to RAID10 all those months ago. The array is now rebuilding parity which means I have a slow as shit computer for the next 6 hours! If it reboots again then it's possible I'll lose the array. Intel's RAID5 driver seems to be buggy as hell; never had a single problem on RAID10. I guess I'll be reinstalling Windows today, the RAID10-RAID5 migration feature is one way only...

03-02-2007, 03:14 PM	#2
Snake Doctor I'm Lenny2 Bitch Join Date: Mar 2001 Location: On top of my soapbox Posts: 13,449	Is this like that teaspoon/tablespoon question that fucked me up on "Are you smarter than a 5th grader?" last night? __________________ sig too big

03-03-2007, 01:24 AM	#5
PHP-CODER-FOR-HIRE Confirmed User Industry Role: Join Date: Nov 2006 Posts: 1,090	Doesn't really matter.... no frequently accessed file is that big anyways. Look in your manual or on Google for stats on your hardware. I'm sure something else is the bottleneck anyways. Also, don't forget that those are optimal figures. Sure, usb2.0 is supposed to do 480mbps, but it doesn't do it for very long. __________________ Hire a PHP Coder

03-04-2007, 07:49 AM	#9
Brad Mitchell Confirmed User Industry Role: Join Date: Nov 2001 Location: Southfield, MI Posts: 9,812	What type of drives were they, ide, scsi, SATA 150 , SATA 3.0 or SAS? Also, what RAID controller? Brad __________________ President at MojoHost \| brad at mojohost dot com \| Skype MojoHostBrad 71 industry awards for hosting and professional excellence since 1999

03-02-2007, 03:33 PM	#3
rowan Too lazy to set a custom title Join Date: Mar 2002 Location: Australia Posts: 17,393	I rambled on a bit but basically I'm asking if those figures are plausible. I guess it doesn't really matter since the array will be back to RAID10 later today.

03-03-2007, 01:15 AM	#4
rowan Too lazy to set a custom title Join Date: Mar 2002 Location: Australia Posts: 17,393	bump5678

03-04-2007, 05:22 AM	#6
rowan Too lazy to set a custom title Join Date: Mar 2002 Location: Australia Posts: 17,393	I ended up having to reinstall Windows twice, realising at the worst possible time that I hadn't backed up the system state. All the executable and config files for my applications have been restored, but Windows itself doesn't know they exist. I've now restored my data only, time to manually reinstall 30 applications.....

03-04-2007, 05:35 AM	#8
rowan Too lazy to set a custom title Join Date: Mar 2002 Location: Australia Posts: 17,393	1143 megabytes per sec is over 9 gigabits per second... Interesting that this is apparently achievable when the drives are gen 1 (1.5Gbps), so the total maximum theoretical throughput of 4 drives is only 6Gbps.