Considering Building Rig - First Time Builder Questions

[ReKK]

Hey! I just first off want to say that I've been reading a lot about unRAID and have found a ton of helpful and friendly posts just learning if it is right for me. I am considering a media storage server and after comparing features between WHS, FlexRaid, & unRAID - I believe unRAID is the best option out there.

 

I understand the idea of how unRAID works - but still am unclear about a few questions I am hoping some of you vets can help me with.

 

1) If you lose two drives of data, but your parity drive is still healthy, will it save at least one of these drives?

 

2) I see that there is a SMART test that you can run to determine the health of your harddrives so that you can prepare for when a hard drive is about to fail. How helpful is this? Is it very rare to lose two hard drives at once?

 

3) Do any of you perform any types of backups to unRAID systems? If so, what kind?

 

4) This is a stupid question, but, how do you get the data onto the server? Do you have to upload to a FTP site from another computer or do you connect another computer to it?

 

 

 

Thanks!!!!!

[jazzysmooth]

1)  No.  If more than 1 drive is failed, Unraid won't be able to determine whether to restore 0s or 1s to each sector.  The parity drive does not contain data, it contains the odd or even result of the summation of each corresponding sector across all drives.  (I'm sure another will explain this in much clearer detail...)

 

2)  Depends if you purchased all your drives at the same time and they came from the same manufacturer / facility.  If a problem develops (like the firmware issue with some Seagates) its possible that it could affect several of your drives if they were all made at the same time.  SMART results will show if the # of relocated sectors is increasing, which is a good indicator that a drive is failing.  Remember that the rebuild process requires Unraid to read from all drives during the entire process, so if you have another drive that is on the edge, that process could very well knock it out.

 

3)  Some users backup to other Unraid systems, or use products like CrashPlan.  Others use their movie DVDs / Blurays as their backups, and others backup items like personal docs / photos on USB drives that they store offsite.

 

4)  Unraid supports SAMBA so you can map drives to it or just use UNC paths (\\server\disk1 or \\server\Movies (if you created a user share)).  You can also mount a drive locally on the server and copy it Midnight Commander, or FTP it, etc.

[Rajahal]

I think jazzysmooth answered your questions quite well, but I'll add a few things:

 

1) No.  unRAID can only recover from a single drive failure without data loss.  However, if more than one drive fails, you only lose the data on those failed drives, you don't lose the whole array (as is the case with RAID 5).  See here for more info: How does parity work?

 

2a) SMART isn't perfect, but it's the best we've got.  Generally I will run SMART on a drive before I add it to the array, but once it is in there I don't check on it at all.  If a drive fails I would attempt to run SMART on it just to make sure it really has failed (and not just a loose connection or something).  If it really has failed then I would replace it and let unRAID rebuild the data.

 

2b) It is fairly rare to lose two drives, however, your chances of that happening increase dramatically if you buy drives in batches.  The best thing you can do to prevent this is to only ever buy one drive at a time, or if you must buy multiple drives at once, buy different brands or buy from different vendors.

 

3) I don't backup my unRAID server.  I do backup all my most important documents both to the server and to all of my and my family's computers using CrashPlan.  My server is basically all just media, and media is replaceable.

 

4) As jazzy said, most of us use SAMBA.  This means that yours server will show up on your LAN (network neighborhood for Windows, just network for Mac).  You can also do FTP and other stuff if you want to, but you don't have to.  You will need a separate computer to access the files on your server, such as a desktop, laptop, or HTPC.