The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

raid virgin

Ben Rubinstein

Active member
Hi,

I'm thinking of making a simple fast setup only for page file/scratch disk use. I've seen 36GB Raptor drives on ebay for very little, thought of buying a couple, set them up as raid 0 (did I get that right? I mean the fast one) and go from there. I blame Jack for the idea, he's the one who keeps exolling the virtues of raid scratch disks!

Couple of questions: Firstly is it Raid 0 I'm thinking of? Secondly are the generic ebay type Raid SATA cards too awful to contemplate and will they work under 64 bit? Thirdly should I bother with Raptor or just go with a single Raptor and forget RAID? I'll be running on a dual core duo 2.2 with 8 gig of RAM under XP 64.

Many thanks and please excuse in advance my lack of understanding of anything more complicated than pidgin technological english!
 

Lars

Active member
Scratch file in Photoshop is very much about transferring large volumes of data and very little about seek speed. Windows page file is a little more about seek speed, but still about transfer speed.

Current regular 7200 rpm drives are plenty fast - and within a year SSDs will come down in price enough to make Raptors obsolete. So don't even consider older raptors, save your money for an SSD upgrade next year. The new Velociraptor drives are wicked fast (and pricey), but even those are on life-support WRT performance compared to up and coming SSDs.

Get two - or three - SATA drives, use Windows Dynamic Disk to set up a striped volume (like a RAID 0) across all drives. You can use parts of a drive, like 10 GB on each drive. This way you get the transfer speed of all drives together, and the seek performance of the slowest drive. Then use the rest for a mirrored volume (like a RAID 1) to keep your data safe.

For best transfer speed performance, put the striped volume at the beginning of each drive where transfer speed is highest.
 

MrSlezak

New member
MaximumPC publised a pretty good write up on the different knid of RAIDs (and they publish back issues in PDF for free) in Nov 2007 or the article is here (if you are not interested the magazine layout).
 

Ben Rubinstein

Active member
Scratch file in Photoshop is very much about transferring large volumes of data and very little about seek speed. Windows page file is a little more about seek speed, but still about transfer speed.

Current regular 7200 rpm drives are plenty fast - and within a year SSDs will come down in price enough to make Raptors obsolete. So don't even consider older raptors, save your money for an SSD upgrade next year. The new Velociraptor drives are wicked fast (and pricey), but even those are on life-support WRT performance compared to up and coming SSDs.

Get two - or three - SATA drives, use Windows Dynamic Disk to set up a striped volume (like a RAID 0) across all drives. You can use parts of a drive, like 10 GB on each drive. This way you get the transfer speed of all drives together, and the seek performance of the slowest drive. Then use the rest for a mirrored volume (like a RAID 1) to keep your data safe.

For best transfer speed performance, put the striped volume at the beginning of each drive where transfer speed is highest.
I could set up 10 gig from each of two current drives to be set up as striped and it will work like raid to give faster speeds? Sounds very nice and easy!
 

Ben Rubinstein

Active member
Aaah, did some research, somewhat more complicated than that. Especially as of my 2 current drives, one is partitioned for two OS's.

I think this is what I would do: Buy a new drive. Convert my old non OS 2nd hard drive to a dynamic disk. Allocate a 10GB volume from the old and new disk and stripe them. Then move my windows page file, PS scratch disk and probably the Bridge Cache to the new striped volume.

That make any sense?

Why the heck isn't Bridge 64 bit? Do you know how much RAM having multiple bridge windows open while generating 100% previews of over 1000 RAW files while working in ACR and PS batch processing in the background uses? Crashes my regular XP system regularly and is one of the main reasons I've finally decided to take 64 bit by the horns and upgrade to 8GB of RAM instead of 3GB.
 
Last edited:

Lars

Active member
Ben,
Yep I think that makes sense. It's good if the two striped drives are approximately equal in terms of transfer speed and seek time.

It's a good idea to not have the boot drive be a Dynamic Disk volume. My boot is two striped Raptors using Dynamic Disk, and if I want to install any non-Windows OS I have to do it on a separate drive.

On my own desktop I have three 300GB disks striped as a work volume. All data is then synced to a network raid box for backup.

BTW Dynamic Disk is only enabled on desktop systems, not laptops. And only Windows OSes understand Dynamic Disk partition tables (AFAIK), so you might not be able to get to the data on any of those drives using Linux. That's what dedicated Raid cards are for - the OS only sees one drive.

Adobe's CS suite is about 80 or so million lines of code. Any of those lines could be 32-bit only, it usually takes a few releases (3-5 years) to bring that much code over to a new environment. I'm sure Adobe engineers have painted themselves into quite a few corners over the years, it can take some time to get out of those corners.

Interesting to see how stable XP 64-bit will be for you. I've run Vista 64-bit for two years now, and I have to say I'm impressed. But it all depends on having good drivers - obviously an issue with XP 64-bit as well.
 

MrSlezak

New member
If I remember correctly, Windows XP - regardless of x86 or x64 - is limited to drive size of 2TB. When XP released that wasn't a practical limitation for folks but with today's drives it could be.
 

Ben Rubinstein

Active member
The question of course is whether you would want to use a 2TB drive given todays needs (maybe if you have a P65!), I really wouldn't like the idea of having that much data on one drive period.

Since I loaded up XP 64 for the 2nd time (formatted the previous load) the system has been pretty much stable period, trick was not to try and load software or drivers that were'nt compatible in the first place. I've just ordered 8GB of RAM and I'm hoping that will make a big difference to my workflow.
 

Ben Rubinstein

Active member
OK, just ordered a HD to match my non OS HD, it's exactly the same one so shouldn't be any issues, when I get it (not for a bit given the time of year!) I'll convert my current 2nd drive to Dynamic, do the same with the new one, then make a striped volume over both for cache, scratch and page file. Together with the new RAM should make a difference!
 

Jack

Sr. Administrator
Staff member
Ben:

One thing to watch out for is even though your second drive is "identical," drive manufacturers often update the drive's firmware. Firmware can affect head seek speeds and latency, so can alter the speeds in which a drives responds. Thus, in an ideal RAID environ, you'd have all identical drives with identical firmware... I only mention this in case you have issues getting your pair of drives to work in RAID. Finally, even drives with the same exact specs may not RAID well for a variety of reasons, and why most drive manufacturers make RAID spec or "enterprise" classes of drives, always more expensive. I personally do not bother buying them since my current WD 640 Caviar's raid just fine, but by way of example, an identical pair of Samsung Spinpoint 1TB drives would *not* RAID-0 reliably on my system so got relegated to the DROBO when it arrived.

Just an FYI,
 

Lars

Active member
Jack:
I believe the Windows Dynamic Disk striping is less picky WRT exact drive specs - I have made striped volumes across five completely different drives, even mixing IDE and SATA drives manufactured between 2000 and 2006. I did this as a test only, performace was limited by the slowest (oldest) drive.
Lars
 
O

Oxide Blu

Guest
Jack:
I believe the Windows Dynamic Disk striping is less picky WRT exact drive specs - I have made striped volumes across five completely different drives, even mixing IDE and SATA drives manufactured between 2000 and 2006. I did this as a test only, performace was limited by the slowest (oldest) drive.
Lars
That makes sense. My understanding (perhaps wrong) is that enterprise HDDs are more robust, a little faster, designed to withstand constant read/write. Doesn't matter if it is RAID'd or not. As far as RAIDing any HDD goes I don't think a drive has any idea what it's being used for. Speed will be whatever the slowest RAID'd drive is capable of.

I like the idea of RAID controllers, either on a separate board or embedded in the motherboard controling the data distribution. OS software controlling RAID scares me a little. But even if s/w controlled perhaps it will be a tad slower but again the HDD hasn't a clue what it is being used for, only that it needs to read/write when told to do so.

The other thing to consider is that RAID 0 (striped) can increase the risk of data loss unless you add add'l drive(s) and get into the esoteric flavors of RAID, i.e RAID 6. Instead of the possibility of an HDD failing, you now have the possibility of any one of 2, 3, or 4 disks failing, doubling, tripling, or quadrupling your risk of data loss. That's where a matrix RAID scheme shines.

Computer stuff is now pretty cheap. You can build a entirely new system with a hardware RAID driver for a few hundred bucks and have a fast application specific system dedicated to photo editing.
 

Ben Rubinstein

Active member
The idea of using RAID 0 only for swap/cache/page file is that the fact that it's not 'safe' makes pretty much no difference at all in the great scheme of things, i.e. who cares if it goes bad, reformat and carry on as usual.

To be honest for RAID solutions which just replicate the data without adding any performance benefits, buying a 2nd drive and backing up the data to it then keeping it offline seems to accomplish the same thing with less difficulties, the only disadvantage seems to be the loss of real time replication but that means real time problems as well such as software corruption, etc. Or is there something I'm not seeing?
 

Jack

Sr. Administrator
Staff member
Jack:
I believe the Windows Dynamic Disk striping is less picky WRT exact drive specs - I have made striped volumes across five completely different drives, even mixing IDE and SATA drives manufactured between 2000 and 2006. I did this as a test only, performace was limited by the slowest (oldest) drive.
Lars
Well good news that you can use the software to RAID-0 mixed drives... I'd be curious as the total performance hit though. When you say limited to the slowest drive, does that mean a three-drive stripe would still run at approximately 3x the speed of the slowest drive? If so, then the software must be pretty sophisticated to keep the write blocks aligned on drives running at different speeds -- :thumbup:
 
Top