Author Topic: New to Flexraid - Before i Begin  (Read 3216 times)

Offline ginjaninja

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New to Flexraid - Before i Begin
« on: September 30, 2011, 02:15:56 am »
The environment.
Win 7 64bit, q6600 @ 3.2Ghz, 6gb ram.
8x2TB Samsung HD204UI green drives (ok in a straight line, terrible random access)
Drives on two SATA-2 HBAs. Intel and Startech
5GB Files, with ancillary meta data.
Occasional writes, new files, to multiple disks concurrently (if the engine allows multiple copy activitys to be run concurrently).

Requirement
recovery from a single disk failure.
ability to backup all data to an independant storage subsystem at intervals

What config  i think i need.
Snapshot raid across all 8 drives.+1 2tb drive for PPU (possibly a high performance drive).  would place a lower dependancy on parity drive at increased risk of dataloss (i am assuming the parity is built/rebuilt on a schedule rather than realtime?)

What i think ill get
ability to read and write to all  the disks at their native speed.
ability to loose a single disk without data loss.

Outstanding Questions?
Does snapshot raid rebuild parity at intervals?
Can i install and un-install flexraid and an array without risk to my data.
would the parity rebuild be confined to the changed data?
what parity rebuild data-rate might i expect?
between parity rebuilds is it only the modified data at risk?


thanks for help, im looking for a bit of advice to get started in a reasonable direction quickly for my application.




« Last Edit: September 30, 2011, 03:05:04 am by xliv »

Offline xliv

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Re: New to Flexriad - Before i Begin
« Reply #1 on: September 30, 2011, 03:02:58 am »
i am assuming the parity is built/rebuilt on a schedule rather than realtime?
Yes, parity is rebuilt (actually not rebuilt but resynchronized) upon request - either manually through the UI, or thanks to the built-in scheduler. In my case: every night.

What i think ill get
ability to read and write to all  the disks at their native speed.
ability to loose a single disk without data loss.
Yes - but you did not mention the storage pooling, are you intending to use it as well? In any case, it's pretty much transparent: the Snapshot is not involved when you read / write data to your drives (except if it's building the parity in parallel).
Yes, with 1 PPU, you are protected against single disk failure.

Does snapshot raid rebuild parity at intervals?
Yes, read above: either manually, or when you've scheduled it.

Can i install and un-install flexraid and an array without risk to my data.
Of course.

would the parity rebuild be confined to the changed data?
Yes. In my case, RAID creation lasted ~12hours (I have ~20TB data), and parity update is around 30mn with usual modifications to my files. The more frequent you update, the more protected you are, and the faster your updates will be.

what parity rebuild data-rate might i expect?
That is limited by your drives and your controller. Most people get around 40-70MB/s

between parity rebuilds is it only the modified data at risk?

Only edited or deleted files put your existing data at risk. And of course new files are not protected.
See http://wiki.flexraid.com/?p=252
Server HW: ASUS P8B-E/4L + PIKE 2008 SAS | Xeon E3-1230 | 8GB DDR3 ECC 1333 [Kingston - KVR1333D3E9SK2/8G] | Intel 320 - 80 Go (OS)
Server OS: Win7 64b EN
FlexRAID 2.0 latest build, Cruise Control, 7 DRUs (6x3TB,1x2TB), 1 PPU (2x2TB)

Offline jasonwc

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Re: New to Flexriad - Before i Begin
« Reply #2 on: September 30, 2011, 07:48:12 am »

Yes. In my case, RAID creation lasted ~12hours (I have ~20TB data). . .

I thought your setup was 6 DRU (3TB) + 1 PPU (3 x 2 TB). Have you added more DRUs? Also, do you have 20 TB of data or 20 TB of storage capacity?
Norco RPC-4224 4U Rackmount Case (24 Hotswap Bays) | Asus P8B Workstation Motherboard (four PCI-E 16x slots @ 8x/8x/4x/4x and dual 82574L Intel server NICs) | Core i3-2100 | Supermicro AOC-SASLP-MV8 SAS Controller | Corsair TX650v2 PSU | Currently 16 TB array, 2 TB parity | WHS 2011

Offline xliv

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Re: New to Flexraid - Before i Begin
« Reply #3 on: September 30, 2011, 08:18:14 am »
good catch ;)
I indeed have 6x3TB data, and used to have 1x6TB PPU  spanning across 3x2TB, but transformed that for some time into 2x3TB PPU drives, but:
- Brahim says it's not recommended to have a drive common to 2 PPUs
- anyway, I'll probably be bying 4TB DRUs soon ;)

So, now I have:
- 6x3TB (which is approx 20TB, but well...), I'm going to add my remaining 2TB drive to that
- 3TB PPU on 2x2TB, will eventually turn into 4TB PP

At one point I assembled all my other drives, and got a 23.6TB - that was just to make a screenshot..
http://wiki.flexraid.com/2011/09/01/why-use-flexraid-view/
Server HW: ASUS P8B-E/4L + PIKE 2008 SAS | Xeon E3-1230 | 8GB DDR3 ECC 1333 [Kingston - KVR1333D3E9SK2/8G] | Intel 320 - 80 Go (OS)
Server OS: Win7 64b EN
FlexRAID 2.0 latest build, Cruise Control, 7 DRUs (6x3TB,1x2TB), 1 PPU (2x2TB)

Offline jasonwc

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Re: New to Flexraid - Before i Begin
« Reply #4 on: September 30, 2011, 09:06:39 am »
good catch ;)
I indeed have 6x3TB data, and used to have 1x6TB PPU  spanning across 3x2TB, but transformed that for some time into 2x3TB PPU drives, but:
- Brahim says it's not recommended to have a drive common to 2 PPUs
- anyway, I'll probably be bying 4TB DRUs soon ;)

So, now I have:
- 6x3TB (which is approx 20TB, but well...), I'm going to add my remaining 2TB drive to that
- 3TB PPU on 2x2TB, will eventually turn into 4TB PP

At one point I assembled all my other drives, and got a 23.6TB - that was just to make a screenshot..
http://wiki.flexraid.com/2011/09/01/why-use-flexraid-view/

What's the maximum drive capacity in your case? 2 TB drives are currently cheaper (just bought two for $60 each) but if you are drive limited, it makes sense to pay a premium for 3 TB, and soon, 4 TB drives. I'm hoping that when 4 TB drives are released the price of 3 TB drives will fall below $100. Since, I spent $110 on my last 3 TB drive, that shouldn't be too far off.
Norco RPC-4224 4U Rackmount Case (24 Hotswap Bays) | Asus P8B Workstation Motherboard (four PCI-E 16x slots @ 8x/8x/4x/4x and dual 82574L Intel server NICs) | Core i3-2100 | Supermicro AOC-SASLP-MV8 SAS Controller | Corsair TX650v2 PSU | Currently 16 TB array, 2 TB parity | WHS 2011

Offline ginjaninja

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Re: New to Flexraid - Before i Begin
« Reply #5 on: September 30, 2011, 01:48:07 pm »
Quote
That is limited by your drives and your controller. Most people get around 40-70MB/s

thanks for advice.
so flexraid is cpu limited on a q6600 @ 3.2ghz with 8 disks? when building parity.

Offline jasonwc

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Re: New to Flexraid - Before i Begin
« Reply #6 on: September 30, 2011, 02:18:52 pm »
thanks for advice.
so flexraid is cpu limited on a q6600 @ 3.2ghz with 8 disks? when building parity.

No, I think you'll be limited by the speed of your drives or your storage controller(s). Remember that the parity build speed measures the write throughput, but in order to build parity, the system has to simultaneously read ALL of your drives. So, if you have 8 DRUs @ 60 MB/sec parity build speed, you're actually reading at an aggregate speed of 480 MB/sec. Because FlexRAID reads from all of your drives simultaneously, you will be limited by your slowest drive, or your storage controller if you can't keep up.

In my case, I achieved a 63 MB/sec parity build with 6 DRU (+2 empty DRU) and 1 PPU. I was only seeing 10-30% cpu utilization on my dual-core i3 chip. However, all the drives were on a Supermicro AOC-SASLP-MV8 controller which isn't all that fast. I'm assuming that's the bottleneck.
Norco RPC-4224 4U Rackmount Case (24 Hotswap Bays) | Asus P8B Workstation Motherboard (four PCI-E 16x slots @ 8x/8x/4x/4x and dual 82574L Intel server NICs) | Core i3-2100 | Supermicro AOC-SASLP-MV8 SAS Controller | Corsair TX650v2 PSU | Currently 16 TB array, 2 TB parity | WHS 2011

Offline xliv

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Re: New to Flexraid - Before i Begin
« Reply #7 on: September 30, 2011, 06:21:11 pm »
What's the maximum drive capacity in your case? 2 TB drives are currently cheaper (just bought two for $60 each) but if you are drive limited, it makes sense to pay a premium for 3 TB, and soon, 4 TB drives. I'm hoping that when 4 TB drives are released the price of 3 TB drives will fall below $100. Since, I spent $110 on my last 3 TB drive, that shouldn't be too far off.
I'm limited to 14 drives with the one I have today.
Server HW: ASUS P8B-E/4L + PIKE 2008 SAS | Xeon E3-1230 | 8GB DDR3 ECC 1333 [Kingston - KVR1333D3E9SK2/8G] | Intel 320 - 80 Go (OS)
Server OS: Win7 64b EN
FlexRAID 2.0 latest build, Cruise Control, 7 DRUs (6x3TB,1x2TB), 1 PPU (2x2TB)