To include "D" or not in the pool

Klode · March 2012

Hi all,

I'm in the process of rebuilding my WHS 2011. I've been testing DrivePool on only 2 out of my 6 drives. Now, after few months of testing, I want to include all drives in the pool. I'm trying to find out if I should include "D" drive in the pool or not. I know client computer backup are stored on that drive. I also noticed some people have issues with their client backup when it's stored on the pool.

1- So, what would be the best advise on this?

2- If I include "D" drive in the pool, what would happen to the data on this particular drive in the event of system drive replacement?

Thanks,

Claude

datageek · March 2012

I have included D in my pool and not had any problems. Existing data on D outside the pool will be unaffected, DrivePool only uses spare capacity, so client backups can stay there outside the pool.

If you need to replace the system drive, any data in the pool that is physically stored on D will be treated in the same way as if you had to replace any other drive with data on it. A couple of scenarios:

A) The old drive still works. In this case, remove all drives except the new one, install WHS and DrivePool (and other add-ins, software etc) on the new drive, power off, re-attach all drives including the old drive, power on, then let DrivePool find all the drives and recreate the pool. All pooled data should still be there. You can then remove the drive from the pool via the wizard (but note that it will no longer be called D, that's reserved for the new D drive when WHS is re-installed). This will move pooled data off the old D drive onto the remaining drives. If there are any non-pooled folders these should be moved across to other drives or into the pool via the Move Folder wizard (I assume there is a way to do this with client backups but I've not tried it). If you want to use the old drive as a data drive, you should then reformat the drive as a single partition and add it back to the pool, this will free up the space used by the old C drive.

The old drive has failed. In this case, any non-duplicated data will be lost, you will need to restore from backup. Duplicated folders should be fine - when you reinstall (as per above but without attaching the failed drive), DrivePool will recognise that duplication is missing on all files that were on D and re-duplicate them onto remaining drives.

Klode · March 2012

The old drive has failed. In this case, any non-duplicated data will be lost, you will need to restore from backup. Duplicated folders should be fine - when you reinstall (as per above but without attaching the failed drive), DrivePool will recognise that duplication is missing on all files that were on D and re-duplicate them onto remaining drives.

Hi, thanks for the info. I guess that means there is 2 scenarios.

1- If you include the "D" drive to the pool, it is safer to enable duplication for all shares since we don't know which data will be on the "D" drive. All data on "D" drive will be duplicated to another drive.

2- If you don't include the "D" drive to the pool, then you can turn on duplication on the shares you want, because there will be no data on "D".

Does that makes sense?

datageek · March 2012

It's always safer to duplicate all folders, whether or not you include D drive in the pool. The only specific reason I can think of for your approach is if you need to be able to quickly reinstall the OS on the same drive - i.e. if you keep D completely empty, you can wipe the drive, re-install and no data will be lost (in theory). Otherwise, bear in mind that any drive can fail, not just the system drive (C/D), so if you have duplication switched off for a pool folder, then any failure of a drive participating in the pool could result in loss of some or all of that data.

Personally, all my data is backed up, I have duplication switched on as an additional layer of protection for folders that:
a) are highly valuable and having one extra copy is a good thing, e.g. my photo collection
b) or have a "high availability" requirement - i.e. I need the data to stay continuously available and not wait to restore it from backup if a drive fails.
c) or are very low in volume so the cost of duplication is negligible

You might also want to consider performance as a factor. I suspect that performance might suffer a bit by having D in the pool (or including any non-pooled share folders on D) due to contention between accessing data files and C-drive files (OS, program files, swap etc). On the other hand, using D allows data to be split across more drives, potentially improving performance when accessing many data files at once. YMMV!

Shane · March 2012

When deciding whether to add a drive to the pool that is also used for non-pool tasks (e.g. if you're dedicating physical disk to client backups or virtual machines) keep in mind that the pool will attempt to balance its content evenly across all its drives including the new one; make sure your non-pool tasks will still have the room they need to perform.

Klode · March 2012

Well, thanks for all advises you gave me. It shed more light on how to proceed with DrivePool. Here is how I managed to use DrivePool:

Drive 0: - C: system disk

Drive 0: - part of pool

E: represents the pooled drives

Drive 1, 2, 3, 4, 5: part of pool

All folders moved into the pool including clients backups

If I find any issue with the clients backups, I will moved them back on "D" and remove it from the pool.

As mentioned, all the drives part of the pool fills up evenly, according to the space left on each drive.

Thanks for all the info, and Alex has made a wonderful add-in for WHS 2011.

Howdy, Stranger!

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