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Defragging Drobo?
03-12-2014, 05:49 AM
Post: #1
Defragging Drobo?
This might sound like a stupid question, but is it possible to defragment the drobo array?

I ask as I am copying over data from multiple hard drives, now I know that this data will be hitting the hard drives in no particular order and the file system will sort it out virtually.

Having had a few hard drive issues it would be REALLY helpful if once I have put all my data onto the Drobo I could defrag it, as I understand this moves data to adjacent data. This is basically damage limitation on my part in case of future issues all my data will be better organised once recovered...
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03-12-2014, 06:53 AM
Post: #2
RE: Defragging Drobo?
Don't do that. Also, it you're using Windows, I'd take care to exclude Drobo from automatic maintenance in Control Panel.
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03-13-2014, 07:01 AM
Post: #3
RE: Defragging Drobo?
(03-12-2014 06:53 AM)Zbig Wrote:  Don't do that. Also, it you're using Windows, I'd take care to exclude Drobo from automatic maintenance in Control Panel.

I'm using a Mac.
Could you elaborate on why its not advisable to defrag a drobo?
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03-13-2014, 09:17 AM (This post was last modified: 03-13-2014 09:20 AM by Zbig.)
Post: #4
RE: Defragging Drobo?
(03-13-2014 07:01 AM)mattchoules Wrote:  I'm using a Mac.
Could you elaborate on why its not advisable to defrag a drobo?

Have you checked the official Knowledge Base article I linked to? It's not advisable because you wouldn't gain anything, only shuffle large amounts of data around needlessly, involving pointless space allocations/de-allocations on BeyondRaid level, etc. BeyondRaid (underlying Drobo technology) creates additional layer of abstraction between the filesystem and the physical disk structure. The actual data on the Drobo is not (or it doesn't have to be) physically stored where the OS has been made to believe it is. And without that awarness, no OS-level tools have much chance of optimizing anything, really. This, plus fragmentation has become less of a problem in modern file systems as they try to keep as much data as possible in contiguous blocks natively and tend to be quite smart about it.
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03-13-2014, 03:36 PM
Post: #5
RE: Defragging Drobo?
Not only does it juggle virtual blocks around needlessly, it might actually break something because Thin Provisioning will tell the OS that there is more space available than there really is. Thus the defrag operation might decide it wants to move a HUGE amount of data because (it thinks) there is enough space and in reality end up using all physical space, causing Drobo to slow to a crawl and (hopefully) stop.

Leave it be. And if you have an automatic defragmenter, tell it not to defrag the Drobo volume(s).

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
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03-14-2014, 05:00 AM
Post: #6
RE: Defragging Drobo?
Zbig: Didnt realise that was a link. My bad.
Thanks for the replies, I'll be a good boy and leave it alone!
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