[Pvfs2-users] Can PVFS over multiple disks on a single node tolerate disk failures?

[Sam Lang]

On Jan 18, 2008, at 2:29 PM, Scully wrote:

> I want to store PVFS data on four disks in the same node. If I don't  
> choose RAID, based on my understanding to <3.2 How can I store PVFS  
> data on multiple disks on a single node?> in the FAQ, I should set  
> four servers, each for a disk.
>
> Can such a system tolerate disk failures?

It would be similar to RAID0 over those disks.  There's no mirroring  
or data redundancy, so a disk failure would cause a loss of data.

> Should I set each disk a metadate server to get the disk failure  
> tolerance?

In your case adding metadata servers won't help, since all the servers  
are running on the same node.  Just pick one of the disks (servers) to  
manage the metadata.

>
>
> I think the <7.3 Can PVFS tolerate disk failures?> in the FAQ means,  
> if I use RAID5 or RAID6 to combine the disks first, then, it can  
> tolerate, am I right?

Yes.  redundant RAID schemes provide for recovery if a disk should  
fail.  Running PVFS servers on-top of RAID5 usually slows down writes  
a little, but if you want to tolerate failures, the performance hit is  
probably worth it.
-sam

>
>
> Thank you.
>
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