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RAID configurations
Hi,
Anyone here up to speed on RAID configurations for hard drives, and how it
relates to image editing?
I was ordering a new PC today, and got 2 hard drives. Asked that they be
configured to RAID 0, which is supposed to use both drives in such a way as
to increase processing speed. ( I have a third external drive that I back-up
to) The sales guy checked with the tech guy who said that unless I'm into
heavy-duty gaming, RAID 0 was a waste. When I said I was a photographer
and artist and will be running CS3, the techie said, "oh, image editing? Nah,
you don't need that much speed". hmmm... does he know what he's talking
about?
I've been making my little 8 x 10 digital positives from scanned medium
format... Now that I've got the photogravure thing kind of figured out, I"m
going to be using the 4x5 view camera, scanning those, and eventually
outputting 16 x 20. Those file sizes are going to be pretty big. I thought I
was going to need as much speed as possible.
Anyone know about this stuff?
Susan
ps... i got the puter anyway, without the raid config. I'm just curious about
this and would like to learn more about computer power as it relates to this 2D
editing we do.
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I use raid 0 for my apps drive and Raid 1+0 for my data
I'd say he is wrong. If you back-up often than you would benefit by Raid 0.
Raid 0 is Striping and it means the data is split across multiple drives. theoretically increasing drive access as you add drives. This doesn't work with all drives so be carefull. Raid 0 is fast and high risk for those who don't back up.
Raid 1 is Mirroring. This is where 2 drives act and look like 1 drive, because they are duplicates of each other: each keeps a back-up of everything written to the raid. this means if you lose a drive you don't lose any data. This is no slower than a regular single drive, but far more secure.
Raid 1+0 uses both Stripping and Mirroring it is the best of both worlds.
I receantly had a drive fall out of my raid 1+0 configuration. I was warned by the drive manager, rebuilt the raid and never lost a step -- it was lovely!
There is also Raid 5 (I think) which is a higher level version of 1+0, but requires a controller smart enough to manage it.
In the pecking order of bang for the buck speed wise I go by the following
1) memory Size
2) Drive access Speed
3) CPU Cache size
4) Bus Speed
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 Originally Posted by SusanV  Hi,
Anyone here up to speed on RAID configurations for hard drives, and how it
relates to image editing?
I was ordering a new PC today, and got 2 hard drives. Asked that they be
configured to RAID 0, which is supposed to use both drives in such a way as
to increase processing speed. ( I have a third external drive that I back-up
to) The sales guy checked with the tech guy who said that unless I'm into
heavy-duty gaming, RAID 0 was a waste. When I said I was a photographer
and artist and will be running CS3, the techie said, "oh, image editing? Nah,
you don't need that much speed". hmmm... does he know what he's talking
about?
I've been making my little 8 x 10 digital positives from scanned medium
format... Now that I've got the photogravure thing kind of figured out, I"m
going to be using the 4x5 view camera, scanning those, and eventually
outputting 16 x 20. Those file sizes are going to be pretty big. I thought I
was going to need as much speed as possible.
Anyone know about this stuff?
Susan
ps... i got the puter anyway, without the raid config. I'm just curious about
this and would like to learn more about computer power as it relates to this 2D
editing we do. Susan,
AFAIAC, not getting the RAID config was a good move if you are talking about the Nvidia on board controllers and software. I've had nothing but problems with two completely different mobos using the RAID controllers and software. The internet is littered with messages from people describing similar experiences.
Get 3 external hard drives, and do son, father, grand father backups and off site storage if possible. Backup image data separately on DVD. You might also consider using A DLT tape drive which are very reliable.
My 2 cents,
Don
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I would argue that the single slowest bit of architecture in desktop computers is the hard disk setup. You can go crazy with fine-tuning the system with SATA, multiple controllers, striping, etc. But perhaps the biggest single bit of advise is this: keep your hard disk less than 67% full and never let it get above that and you will have a happy system that performs better than most other "tweaked" systems that approach their capacity. The reason is simple: the fastest tracks are on the outside of the hard disk platter and once you get beyond 50% full you are reading/writing to the inside tracks which can be as much as 50% slower.
In short, buy yourself plenty of hard disk space first and worry about RAM second (which is somewhat contrary to conventional wisdom). I like the suggestion of primary (fast), secondary, (medium speed), and tertiary (network backup drives which are technically quite slow) as a reasonable system, but bear in mind that sooner or later you will fill it all up anyway, so designing it up front and sticking to deliberate backup strategies will serve you well for years to come.
Speaking of which, offline harddisks (e.g. removable 250Gb drives) are probably cheaper per megabyte and more feasible than DVD backup for most serious photographers.
Cheers,
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You should have at least two internal drives. Having one internal disk for both OS pagefile and PS scratch disk is not a good way to go, as the OS and PS will fight for access.
If all you have on your system is two hard drives than a raid won't be helpful, because the OS will see the raid as one drive and you'll have the problem I described above.
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I have just finished setting up a new Mac Pro. I already had an external RAID system that I just transferred to the new system. That is a nice way to go, since it makes the migration process painless. This external setup has 5 disks, and I have it arranged with one striped RAID 0 array of 3 disks, and one of 2 disks. I backup the big array to the small array every night with a backup program that essentially clones the volume. When the 3 disk array starts approaching capacity, I will just get another 5 disk array, and make it a 5 disk RAID array, transfer the data to the new box, and then reconfigure the old box to a 5 disk array. Bottom line is that it is fast. You can really notice a difference when working on a large file with a lot of layers.
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Hi Michael, ... the box I've ordered is huge, and has room for 4 hard drives.
As ordered it will have 2 250GB serial ATA 3Gb/s, 7200rpm drives. As money
allows I will add drives. I also already have an external drive that I have set
up to back-up image files every evening. I agree that the price of external,
and/or removable drives makes them seem like a good value for using as
backup. I will keep in mind what you said about drive capacity and speed.
Didn't know that!
Jd... regarding bang for buck, I got 2GB dual channel ddr2 @ 667MHz, and
there is room to double that. Intel core 2 duo E6420 with 4MB L2 cache,
2.13 GHz, and a front side bus speed of 1066. Good point about the 2 hard
drives and raid, and how that wouldn't work well for a ps scratch disk... that
never occurred to me. In fact... that single point might be the deal-breaker
as far as using a raid 0 configuration when the primary task of the machine is
photoshop, as mine will be. I was thinking that later on when I add other
drives I might set them up as raid 0, but since PS always "looks to" it's
scratch disk, THAT is where speed would be a good thing... as in a 10000 rpm
drive. (?) I'm kinda confused about this now... the scratch disk and how it
relates to raid config.
See this is the thing when dealing with tech people about my (our)
computers... I have a hard time finding people who understand the photo
editing process that we do. When most of them hear "photo-editing" they're
thinking of fixing red-eye in family snaps. They don't understand the "need
for speed". haha... Right now I'm using an OLD pentium 4, and when I apply
unsharp mask, I go play fetch with the dog while it's working at it. Man o
man... the dog is gonna hate this new computer 
Clay, it took me a couple of reads to visualize your system, but I got it, and
wow that sounds like a great way to do it.
ok gotta go clear my head of all this techie stuff for a while and make some
art to pay for my new machine
thanks for the education... keep it coming!
Susan
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One thing I failed to mention on this new system was that it had 3 extra internal SATA drive slots. I shopped around and found a deal on three 7200RPM 80GB drives (around $65 per drive) and installed them into the empty bays. I configured them as a RAID 0 striped array (it looks like one large virtual disk). I keep this drive basically empty and use it as the photoshop scratch disk. Because of the striping and the fact that it is hooked right into the system bus, my photoshop speed has improved radically. Just for grins, I loaded a 600 MB image file from a large format drum scan, added five layers and then did a few editing things and USM etc.. This would have left my old system panting for breath, but the dedicated scratch disk array makes this feel like a 6megapixel jpeg in photoshop.
Originally Posted by SusanV Hi Michael, ... the box I've ordered is huge, and has room for 4 hard drives.
As ordered it will have 2 250GB serial ATA 3Gb/s, 7200rpm drives. As money
allows I will add drives. I also already have an external drive that I have set
up to back-up image files every evening. I agree that the price of external,
and/or removable drives makes them seem like a good value for using as
backup. I will keep in mind what you said about drive capacity and speed.
Didn't know that!
Jd... regarding bang for buck, I got 2GB dual channel ddr2 @ 667MHz, and
there is room to double that. Intel core 2 duo E6420 with 4MB L2 cache,
2.13 GHz, and a front side bus speed of 1066. Good point about the 2 hard
drives and raid, and how that wouldn't work well for a ps scratch disk... that
never occurred to me. In fact... that single point might be the deal-breaker
as far as using a raid 0 configuration when the primary task of the machine is
photoshop, as mine will be. I was thinking that later on when I add other
drives I might set them up as raid 0, but since PS always "looks to" it's
scratch disk, THAT is where speed would be a good thing... as in a 10000 rpm
drive. (?) I'm kinda confused about this now... the scratch disk and how it
relates to raid config.
See this is the thing when dealing with tech people about my (our)
computers... I have a hard time finding people who understand the photo
editing process that we do. When most of them hear "photo-editing" they're
thinking of fixing red-eye in family snaps. They don't understand the "need
for speed". haha... Right now I'm using an OLD pentium 4, and when I apply
unsharp mask, I go play fetch with the dog while it's working at it. Man o
man... the dog is gonna hate this new computer
Clay, it took me a couple of reads to visualize your system, but I got it, and
wow that sounds like a great way to do it.
ok gotta go clear my head of all this techie stuff for a while and make some
art to pay for my new machine
thanks for the education... keep it coming!
Susan
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My understanding is that RAID performance can really depend on the hardware configuration and how it's controlled.
RAID 0 gives you incredible write performance because it can send 1 block of data to the 1st drive and the controller doesn't have to wait for that to finish writing before it sends the next block to the next drive (although whether your computer can take advantage of this will depend on how the RAID works). Now my understanding is that read performance isn't going to be any better than a single drive because you're waiting for 2 drives to seek to the right spots and the data probably has to be sent back sequentially anyway.
For RAID 1 your write performance can suffer since you have to write to 2 disks before you move on. If you have each drive on a separate channel or controller though you should be able to do this simultaneously so you should have the same performance as a single drive. If they're on the same channel you may have to wait for the 1st disk to finish writing before the 2nd disk is written too which will make things really chug.
As mentioned, RAID 1+0 gives you the best of both worlds.
If you use a good backup strategy, then I'd be more inclined to go with RAID 0 just because of the economics (more bang for buck in terms of storage space).
Personally though? I'd say the best 2 drive setup for a personal computer is 1 drive for OS and a separate drive for data. That way your OS drive can completely fail and your data should be fine, you can even take that 2nd drive to another computer if you need to. And it makes reinstalling your OS a lot easier. I probably wouldn't do a RAID setup unless I had 3 drives (1 drive for OS, 2 drives in a RAID for data).
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To my knowledge everything Frugal said is true.
Originally Posted by frugal
Personally though? I'd say the best 2 drive setup for a personal computer is 1 drive for OS and a separate drive for data. That way your OS drive can completely fail and your data should be fine, you can even take that 2nd drive to another computer if you need to. And it makes reinstalling your OS a lot easier. I probably wouldn't do a RAID setup unless I had 3 drives (1 drive for OS, 2 drives in a RAID for data).
This is my layout. I have 6 sata drives. 2 80 gig's set up as raid 0 for the OS and Apps and 4 500 gigs set-up as raid 1+0 for data. It is fast and reliable.
You need to buy drives that are built for raids. Many consumer level drives are not suitable and at the other end many of the 10k rpm drives tend to be shorter lived. I bought better quality 7k drives. They were30 to 50% cheaper than the 10k drives and about or slightly higher than the cost of the avg consumer 7k drives. One last consideration is case temp. Over heated equipment, including HDD's are an issue so good ventilation is important.
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