Hiya,

 

First post here. Looking at unRAID for a 15 drive media server and was wondering why the manual says to stop > shut down > replace/add > turn back on to add or replace a disk.

 

It seems a bit weird to be selling complete servers with hot swap caddies when the OS can't actually hot swap, so just wondering when this is coming

 

Also is it possible to have double parity, as in raid-dp? And what happens if the USB stick fails. Is there a way to restore to another stick?

 

Thanks

It seems a bit weird to be selling complete servers with hot swap caddies when the OS can't actually hot swap, so just wondering when this is coming

Not is the near future.  The hotswapo bays are just for easy of adding and changing drives.  It takes almost no time to shutdown, remove, and replace a drive, so this is not high on the list of things that need to be added.

 

Also is it possible to have double parity, as in raid-dp?

There is no current RAID6 like functionality.  It has been talked about a lot by the community and is something that will probably be added eventually.  You can do a RAID 1 on the parity drive using a hardware RAID controller but that gains you virtually nothing.

 

And what happens if the USB stick fails. Is there a way to restore to another stick?

That is the main reason a 2 pack is sold.  Generally Lime-tech has sent out a new .key file for the new USB stick to replace the one that failed.  Make regular copies of the one you run with most of the time and when it fails you can copy everything over and the replacement should work just fine.

Thanks.

 

The benefit of having protected parity, or double parity (dedicated disks in raid-dp) is that if one of the parity drives fail it doesn't have to rebuild the parity on that drive from all the other disks, just the second parity drive.

Thanks.

 

The benefit of having protected parity, or double parity (dedicated disks in raid-dp) is that if one of the parity drives fail it doesn't have to rebuild the parity on that drive from all the other disks, just the second parity drive.

 

But unRAID, as of right now, has no concept of dual parity.  If one were to fail you would have to swap it out with your "good" one, which would involve some command line stuff to make the make unRAID think it was not a new parity drive.  A parity check would still be needed though (at least I think it would) to make sure data and parity were in sync.

Double parity gains you practically nothing.  The parity drive is no more important to protection than any data drive.  Having a copy of it is worthless if you lose a data drive.

If the parity drive is worthless if you lose a data drive, what is the point in the parity drive in the first place?

 

Doesn't the parity drive rebuild data if a failed drive is replaced, like in traditional RAID systems?

If the parity drive is worthless if you lose a data drive, what is the point in the parity drive in the first place?

 

Doesn't the parity drive rebuild data if a failed drive is replaced, like in traditional RAID systems?

 

A complete duplicate of the parity drive is nearly useless.

 

The parity drive does allow you to recover a failed data drive like a traditional RAID does.  It just works slightly differently.

 

You are better off duplicating the content of a data disk then the 1's and 0's on the parity drive.

If the parity drive is worthless if you lose a data drive

 

I didn't say the parity drive was worthless.. I said double parity was worthless.  You only need one parity drive, and having a copy of it does not help a bit if you lose a data drive.

Lets compare - 20 data drives and 1 parity drive vs 20 data drives and 2 duplicated parity drives. Which is more likely to fail, a data drive or a parity drive? Also, with the duplicated parity case, it really doesn't matter if the duplicate drive fails.

 

The only way another parity drive helps is if the second drive would allow the failure of 2 drives at the same time.

 

Peter

 

Hiya,

 

First post here. Looking at unRAID for a 15 drive media server and was wondering why the manual says to stop > shut down > replace/add > turn back on to add or replace a disk.

 

It seems a bit weird to be selling complete servers with hot swap caddies when the OS can't actually hot swap, so just wondering when this is coming

Thanks

 

Hot swap caddies are just part of the issue.  Most desktkop motherboards don't have onboard hot swappable sata ports.  You can add hot swappable adapters but the onboard ports will still not be.  This works well enough because I plug my unRAID array drives into the non-hot-swap ports and I keep some that are hot pluggable to work with SNAP.  So, be careful of which ports you do that with.