We have 4 chassis unity 5 medianet. There are two spare drives in each chassis. I'm told all 4 chassis are combined into on work group. So excluding the 2 spares in each 16 drive chassis that's a 56 drive work group. I've been told that it is more common to have work groups made up of a single chassis. This makes sense to me given if one of the 56 drives goes bad that will effect the entire unity, won't it?
So here's some basic questions I have. Doesn't every file get spread across all 56 drives or is there something more subtle as to how the unity distributes the media in the work group? If every file gets spread across all drives then with a drive failure doesn't every file get affected? Given the only protection on unity is mirroring won't the mirror be affected with a single drive failure if the media is truly distributed to every drive in the work group?
My very limited understanding of the spare drives is that if a drive in the work group starts acting up there is a way to have the unity bounce the problem drives media to one of the spares so the unity can continue to work without interruption. This would work with a failing drive, which I'm told is detected by looking at the access time to the drive and noticing it taking longer than usual. What other criteria flag a failing Unity drive?
What happens when one of the drives in a work group just dies a sudden death? In my simplistic view, assuming everything is optimized won't virtually every file be effected? I'm sure the system can't be that fragile so what particulars am I unaware of?
John Moore
Barking Trout Productions
Studio City, CA
bigfish@pacbell.net
Barking Trout Productions
Studio City, CA
bigfish@pacbell.net
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Posted by: John Moore <bigfish@pacbell.net>
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