Hi

Any plans for adding some kind of defragmentation utlity?

 

mani

Why is there a need?

This has been explained.

 

 

This is not an expert answer, just my understanding.  As far as I know, there are no defrag tools for the Reiser file system.  However, I also understand that ReiserFS is highly resistant to large file fragmentation, which I assume means that it preallocates space ahead of a growing file.  With unRAID, if you write to a User Share configured to use a Cache drive, then files should also be completely contiguous, because they are rewritten to their destination drives one file at a time.

In addition to the file system's succeptability - or lack thereof - to fragmentation, fragmentation tends to occur in the use case of frequent write/deletes.  Most (but certainly not all) Unraid uses are frequent write/reads.

 

 

Bill

Actually there is a frag check script or two kicking about. Will see if i can find the link.

 

Theres alot of assumption going on here that real life implementation of rFS matches the theory. I tend to agree that a tool isnt needed but it would be nice to have some empirical evidence.

http://forums.gentoo.org/viewtopic-t-429915-highlight-defrag.html

 

Never actually tried it

Well, now that I have over 700 DVD movies on my unRAID, I would like to resurrect this topic of defragmentation.

 

I understand that most of the time, unRAID array should not need to be defragmented since its normal use is write-once and read-many.  However, what happens when I replace my 700+ DVD movies with the high-definition Blue-Ray version?  I don't plan on keeping the DVD copies and will (actually already started) delete them from unRAID prior to adding the Blue-Ray version.

 

Will this not cause a large fragmentation in unRAID because the deletions and additions are random across disks and the amount of disk space freed (4-6 GB per SD movie) won't correspond to the disk space required (25-35 GB per BD movie)?

 

How are other people handling the replacement of their SD movies to BD movies?

Deleting 4GB DVD images, and saving 40GB BR images over them, will not create significant fragmentation.  A 40GB file in 10 to 100 fragments is not anything to worry about.

 

Even so,  playing BR, at the max possible per the BR spec of 40Mbps, can be done from a drive with horribly bad fragmentation, with no issues.

I have to agree with what BubbaQ stated. There shouldn't be any need to manually defrag.

 

File level defrag IMHO cause more of a problem especially if you have spun down disks.

Thanks for the information, I will stop worrying about fragmentation when updating to HD movies.

I think easiest way to simulate a defrag would be to copy the contents of a disk to an empty disk in the array.

never copied between disks on an array, this is possible isn't it?

Yes, copying everything off one disk and onto another disk will "defrag" everything.