Can I change the stripe size without loosing data?

Mint_Sauce

Mint_Sauce

Mint_Sauce

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I've been reading about onboard controllers in an attempt to save some cash over buying a dedicated hardware raid card. So far, i've found that you can get huge increases in performance with onboard just by changing the strip size to 32kb (for a 5 drive array). Apparently due to the onboard controller being "dumb".

Anyway, I'd like to give it a go before splashing out any money on a dedicated card and was hoping there's a way of changing the stripe size on the fly without loosing all my data. I can't copy the data off as there's over a TB of work photos on here!

Can something like partition magic do this stuff without data loss?

EDIT: Have been reading up on it and seems you can't change the stripe size without starting over. :( So, my new plan is to buy 2x1tb drives and use them in my NAS which currently has 1x 500gb hdd in. Then I can not only back up all my data (which I need to do anyway) but would also allow me to try a new stripe size/experiement then if that fails lump the cost of a proper raid card.

Can anyone recommend some good 1TB or 750gb drives that are reliable? :)
 
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Surely if you do an image with something like Acronis true image and then re-create the array and plonk the image onto the newly striped array, this would work.

That way, you setup a 4 drive array at first (or even 3) put the image on the 'spare' 2 drives (if more than one is needed) and then copy the image back on to the 3 drive array and expand it to use all drives.
 
he's already said he doesn't have the space to store a 1TB image and doing your process after he buys more drives doesn't make sense anymore :)

mint_sauce - stripe size has nothing to do with the onboard controller being 'dumb' ...basically the bigger the files you're working with on the array the bigger stripe size you want.

e.g. i'm currently running a 1MB stripe size on my raid 5 because i'm hosting mostly large files on it and i see better performance this way, for an O/S you're most likely better off with 32/64.
 
marscay said:
he's already said he doesn't have the space to store a 1TB image and doing your process after he buys more drives doesn't make sense anymore :)

mint_sauce - stripe size has nothing to do with the onboard controller being 'dumb' ...basically the bigger the files you're working with on the array the bigger stripe size you want.

e.g. i'm currently running a 1MB stripe size on my raid 5 because i'm hosting mostly large files on it and i see better performance this way, for an O/S you're most likely better off with 32/64.
Click to expand...
Imaging compresses volumes. Even with over 1TB data, this should compress to about 75% (depending on the photo format, it may be already in a compressed form, unless it is a bitmap) 750GB is not a stretch. To run a RAID5, you need 3 drives minimum and he is asking about 5 drives. I'm assuming that he meant 5x 500GB drives since he mentions one, in which case 2 x 500GB drives would hold the image, making my process work. Though this is based on assumption and we would need more info on the setup he is running now.
 
All my files are in .dng and .cr2 format.

My current set up is 5x500gb in Raid 5 and in my NAS I just have the one 500gb although this is half full of rips I did from family VHS. :(

Not sure what to do, SiSoft Sandra confirmed my fears and puts my raid write speed at around 32Mb/s :(

Code: 
Benchmark Results
Drive Index : 132 MB/s
Results Interpretation : Higher index values are better.
Random Access Time : 14 ms
Results Interpretation : Lower index values are better.

Windows Experience Index
Current Drive : 5.9
Results Interpretation : Higher index values are better.

Performance Test Status
Run ID : 28 March 2008 at 01:16:33
Platform Compliance : Win64 x64
System Timer : 3.6MHz
Operating System Disk Cache Used : No
Use Overlapped I/O : Yes
I/O Queue Depth : 4 request(s)
Test File Size : 8GB
File Fragments : 7
Block Size : 1MB

Detailed Benchmark Results
Buffered Read : 2436 MB/s
Sequential Read : 228 MB/s
Random Read : 54 MB/s
Buffered Write : 3048 MB/s
Sequential Write : 32 MB/s
Random Write : 18 MB/s
Random Access Time : 14 ms

Drive
Drive Type : Hard Disk
Total Size : 1863GB
Free Space : 880GB, 47%
Cluster Size : 4kB

Physical Disk
Manufacturer : Intel   
Model : Raid 5 Volume
Version : 1.0.
Serial Number : henarray
ANSI SCSI Approved Version : SCSI-4
Rotational Speed : 28524rpm (estimated)
Removable Drive : No
Queueing On : No

Performance Tips
Notice 5008 : To change benchmarks, click Options.
Notice 5004 : Synthetic benchmark. May not tally with 'real-life' performance.
Notice 5006 : Only compare the results with ones obtained using the same version!
Notice 5209 : Consider using the Removable Storage/Flash Benchmark for Flash devices.
Tip 5202 : Use cache on to measure Windows performance.
Warning 5205 : Low write index. Check write verify is off.
Tip 2 : Double-click tip or press Enter while a tip is selected for more information about the tip.
 
Hmm, it might be possible my suggested method, but it would certainly be time consuming.

One thing to note is that whilst the stripe size will affect performance, your writes will not be changed because without a dedicated XOR processor to handle parity calculations, your writes will always be offloaded to the CPU. Your reads would change though.

What you really want is a hardware RAID5 card. I suggest Areca cards, but cost wise, this would be hefty (~£400 for the quality of card you really need).
 
mint sauce - smids is absolutely correct, if you're after more write speed on your R5 array a hardware card is the only way to do it.....stripe sizes won't have much of an effect in R5 with onboard.

you don't have to go Areca though, they're good but over the top for most home users imho and there's other ways to get similar performance for a 1/4 the cost ;)
 
I've been eyeing up the Highpoint Rocketraid 3520 which can be had for £286 which is 8 port and looks pretty good.

With the onboard stripe size thing I was talking about, some guy did a lot of tests and noticed his write speeds jumped to ~220MB/s. He nailed it down to getting the right stripe size and also a few other things so that data coming in wasn't converted more than it had to be or something. :D I think it was to do with the different stages and having a certain size meant the onboard controller didn't have to think about certain things meaning it would be faster. I can't find the link now, typical..

I'm seriously just considering getting a 750gb drive for my NAS box and then also spending out on a proper Raid card just to get it sorted. Which 8 port Raid5 card would be a good bet, I've checked out the rocketraids which look great but mixed feedback around the internet on their reliability.

The Dell Perc 5i cards, I would need an 8 port jobby, I don't want to buy the wrong thing on eBay, which one would I need to buy to support my drives?

Thanks for all the help, I'd be up **** creek without it.
 
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I've had no problems with the 8 port RR2320 but it's not a true hardware solution, it a half way house "accelerated software" solution so it's not as fast as the likes of an Areca 1210 but still turns in 80MB/s or so writes.

The RR3xxxx series cards use the same Intel IOP processors as the Areca cards so should give similar performance.
 
marscay said:
mint sauce - smids is absolutely correct, if you're after more write speed on your R5 array a hardware card is the only way to do it.....stripe sizes won't have much of an effect in R5 with onboard.

you don't have to go Areca though, they're good but over the top for most home users imho and there's other ways to get similar performance for a 1/4 the cost ;)
Click to expand...

Heh, but hey, the Areca's are a complete solution, if nothing else. There are alternatives though, I just happen to trust Areca. :p
 
i can give you some pointers on the Perc 5/i coz i'm running one myself with 4 1TB WD RE2's, you're best bet is to buy from the states as they're generally pretty hard to source for a good price here....YMMV :)

if you don't mind getting a little dirty you will save a packet and still get over 200mb/s writes, i expect to see over 300mb/s writes on my array once i add another drive or 2.

i'm definitely glad i saved the 300-350 quid by grabbing a Perc, they're just rebadged LSI 8408E SAS cards ....i've flashed mine back to a LSI :)
 
marscay said:
i can give you some pointers on the Perc 5/i coz i'm running one myself with 4 1TB WD RE2's, you're best bet is to buy from the states as they're generally pretty hard to source for a good price here....YMMV :)

if you don't mind getting a little dirty you will save a packet and still get over 200mb/s writes, i expect to see over 300mb/s writes on my array once i add another drive or 2.

i'm definitely glad i saved the 300-350 quid by grabbing a Perc, they're just rebadged LSI 8408E SAS cards ....i've flashed mine back to a LSI :)
Click to expand...

I've got one of those sitting in a box behind me. I've not used it in a while... I want to flash it back to an LSI - you got any tips/guides on how to do it. I hate the Dell firmware and Server 2003 limitation. I want to be able to use it for XP properly, without having to faff around with the drivers.

I know Areca aren't the only one, but they are always consistently good performers. Highpoint are decent, LSI are much the same. I like some of the Intel, HP and IBM controllers, but then you get some with great potential like Promise or 3ware who have screwed it up in the past.
 
yeh use LSI's MSM software within windows to flash to LSI firmware.

you'll need to add the dell vendor id's into the LSI .inf file if you want to use their drivers too, although i think the dell drivers still work ok with the LSI fw also lol, but they're slower at releasing them.

best bonus is you can also use 512mb cache with LSI fw.

i'd agree with you there, i don't like promise controllers but the rest are generally pretty good.
 
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Found an 8 port Perc card from Germany, looks ideal as far as I can tell.

DELL PERC 5/i 256MB @ 8-Port SAS/SATA zu PCI-E RAID

Found on a popular auction site (can I link to it?)

I think this is exactly what I'm after. Can anyone confirm so I can get it ordered? :)
 
Mint_Sauce said:
Found an 8 port Perc card from Germany, looks ideal as far as I can tell.

DELL PERC 5/i 256MB @ 8-Port SAS/SATA zu PCI-E RAID

Found on a popular auction site (can I link to it?)

I think this is exactly what I'm after. Can anyone confirm so I can get it ordered? :)
Click to expand...

It's what I have, and marcsay too. So long as it is the version of the card which does RAID5, as there is another type which only does RAID1, 0 and 0+1.

Can't link to it, I'm afraid. That sounds like the right piece of equipment though.
 
Great, bought it! It was the Raid 5 version and also purchased the backup battery which wasnt much more. Can't be bad for £146 delivered. Thanks loads for all the advice and info, you all saved me a packet! :)

EDIT: Oops, need some of those cables from the Perc to my SATA II drives, where can I get them from?
 
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What you need is an SFF 8484 to 4x SATA cable fan-out. Generic ones cost about £10, but you'd need two. Can't help you out on links, but google will help =/.
 
Just bought two of these cables.

SAS/SATA Internal Cable 50cm Multilane to 4x SAS FanOut (SFF8484 to 4x SFF8482)

Hope I got it right!
 
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