Best Block Size in Raid for Photo files

Question

Best Block Size in Raid for Photo files

I am setting up my two drive striped RAID 0 and came to a screeching halt at the raid block size.

This RASID is strictly for photo scans and PS CS2 photo files, mostly high res, some medium JPEGs.

Adobe says PS CS2's default block size in 64K, if I can believe the technical support guy, who said it off the top of his head, after not understanding what I was talking about.

Apple Tech support first knew nothing about it. Then, after checking all over for quite some time, said 32K is adequate for what I am doing but 64K is alright. In other words, he said nothing.

What would be the best block size for my purpose and why.
One scan file size that I just checked is 135.2MB, another 134.6 MB and that is typical. JPEGs are, of course, smaller, ca 284 KB. Photos with the Canon EOS-1Ds Mk II run 9mb up to 200mb after processing. No other tyhpes of files will be on this drive.

What would be the ideal block size and why?

Thanks much,

Mark

G5 dual 2.5G, NVidia card and 30 display., Mac OS X (10.4.2)

Posted on Sep 13, 2006 1:11 PM

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Answer 1

The hatter

Level 9

60,990 points

Sep 13, 2006 2:09 PM in response to Mark B Anstendig

The default 32K is for small random I/O pattern of a server. Use 128/256K for audio and video files. And 64K for workstation use.

the larger block size gives the best performance for sequential I/O. Someone mentioned an AMUG review of CS2 tests that showed that 64K.

Because this is probably a scratch volume, you could always test for yourself, and rebuild the RAID later and try a different scheme. Sometimes that is the best way to match your drives, your workflow, and system. There are a couple CS2 scripts and benchmark utilities to help get an idea of how long each step or operation takes.

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Answer 2

Sep 13, 2006 2:26 PM in response to Mark B Anstendig

I would go for 64K. I personally went 32K given my RAID drive is also my boot drive and the vast majority of my disk access are for small data chunks.

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Answer 3

Sep 13, 2006 2:32 PM in response to The hatter

Thanks for the info.

At just about 70 years of age, I would prefer settling on a recommended size and getting on with the things I want to do in my possibly limited time left on this planet.

From what you say, it would seem 64K would be good for Photoshop. I refuse to listen to digital audio as yet, especially CDs, and do not do video. Just stills.

I'll wait, though, to see if anyone has specific experience with Photoshop and scanner photo files.

Thanks again for the thoughts,

Mark

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