Power loss during drive expansion/repair/sync

Hello,

There is a distinction While the NAS can recover and start from where it left off with an expansion, during a rsync of a drive, it does not recover in the same manner. If the NAS was to lose power during a rsync a hot add may get the drive to be recognized again, however you may need to 0 fill the drive before adding it again. It should not damage the drive in any manner however it does not recognize it as a part of the array at that point. Also while the expansion should recover nothing is fail proof. With that being said it is always in your best interest to keep a current backup of your data, as anything can happen.

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You can connect a UPS to the NAS. A UPS with a USB port can be send monitoring alerts over the USB cable (must be USB, serial-to-USB will not work) to safely shutdown a NAS in the event of a power failure. Of course the power cable for the NAS must be connected to the UPS too. Most APC units are compatible provided they have a USB port. The NAS doesn't need much time to shutdown.

You can even share a UPS across your network with other ReadyNAS units or even client machines (Using the ReadyNAS to create a Network UPS for PCs). Of course the power for the NAS units/client machines and for the router/switch would also need to be connected to the UPS for this to work.

One should always make sure they have a current and complete backup before making any change to any NAS. Remember Murphy's law - "Anything than can go wrong, will go wrong". While I have never had a problems with expansion or resyncing in the 4+ years I have had a ReadyNAS NV+ and the 1 1/2 years I have had my NVX units, members have had problems. Recovery is always much easier with a current and complete backup. Never trust your data to any one device at any time.

Thanks for all your replies.

readysecure1985 wrote:
during a rsync of a drive, it does not recover in the same manner. If the NAS was to lose power during a rsync a hot add may get the drive to be recognized again, however you may need to 0 fill the drive before adding it again.

I'm new to this so might have used the wrong terminology in my first post. Just to recap; If I replace a failed HDD and begin the process of rebuilding the volume - if the power is lost part way through, the data transfer to the new disk would be incomplete, and at worst (theoretically) I'd just need to start the rebuild process again from the beginning? Data on the other disks in the array shouldn't (again, in theory) get corrupted?

In any case, I've come round to the conclusion that I need to have a copy of my data elsewhere.

PapaBear; Agreed. I've ordered three 2TB HDDs, so I'll use two for the NAS and fit the third into an external USB hard drive enclosure for backups.

Because of the flooding in Thailand, I decided to order the disks early - and got them from Amazon hours before they sold out. Other suppliers are now charging double what I paid for them...

Wise move. I bought some 3TB drives this past summer to expand two of my NAS units and the drives are now twice what I paid for them. Makes we wish I had bought more.

I think I now recall losing power during a resync (after replacing a drive) and when power was restored it picked back up and continued. But, I would not guarantee that. Like any safety net feature, they work better if you have a plan B (backup) available. I have two copies of all data and four copies of critical/important data, but then I have lost data in the past (complete drive on a PC) and don't want that to happen again.