First Server

[Rix001]

I have a fairly extensive Plex system which I have been running just piggy backed to a Desktop. I am looking at UnRaid as a way of protecting that data. I have a Desktop that I will dedicate to be my UnRaid Server. This box has a new 850 watt Power Supply, plenty of Sata 3 plugs, and a Intel Quad Core processor with 4GB ram.  I have purchased  6TB drive for my Parity drive and three 4TB drives for data storage. My desktop currently is running Windows 10 Pro on a 250GB SSD. I have several questions about UnRaid. Will UnRaid work as a stand alone OS or do I have to have Windows running also. I’d like to use the 250GB SSD as the cache drive but Windows eats up a lot of the available space. I have one 4TB drive now already with data on it from Plex, do I have to remove all that data, build the array, then copy it back, or can I just plug the drive in with the data intact? I assume the Parity drive needs to be empty? Just to clarify my understanding, I can add more 4TB drives as needed without adding another Parity drive? 

Thank you for the assistance. 

[trurl]

1 minute ago, Rix001 said:

Will UnRaid work as a stand alone OS or do I have to have Windows running also.

Unraid IS a stand alone OS. There is no way to run it within Windows.

 

2 minutes ago, Rix001 said:

I have one 4TB drive now already with data on it from Plex, do I have to remove all that data, build the array, then copy it back, or can I just plug the drive in with the data intact?

Unraid must format any disk it will use in the parity array or as cache. You can access disks outside the array with the Unassigned Devices plugin.

 

3 minutes ago, Rix001 said:

I assume the Parity drive needs to be empty? Just to clarify my understanding, I can add more 4TB drives as needed without adding another Parity drive? 

Doesn't matter whether it is empty or not, because every bit of it will be completely overwritten with parity.

 

A single parity drive PLUS ALL other disks will allow you to recover a single failed disk, regardless of how many disks are in the array. A second parity disk would allow 2 simultaneous failures to be recovered. Failures can be for reasons other than a bad disk. Bad connections are more common.

 

Note that parity by itself cannot recover anything. And parity is not a substitute for backups. You must always have another copy of anything important and irreplaceable.

[JonathanM]

43 minutes ago, Rix001 said:

I am looking at UnRaid as a way of protecting that data.

 

35 minutes ago, trurl said:

parity is not a substitute for backups. You must always have another copy of anything important and irreplaceable.

Just wanted to pull out the bottom line takeaway here.

 

Unraid can emulate and rebuild data on a failed drive, 2 if you have 2 parity drives. It can NOT protect against user error, file system corruption, or any of the myriad of other threats to your data.

 

You MUST have a backup strategy in place if you want to protect your data.

[Rix001]

Sorry for my lack of knowledge but if I’m configured with a 6TB Parity and three 4TB data drives and I experience a drive failure, UnRaid can not reproduce the data on a new 4TB? If one to one drive backups are the only way to accomplish this why would anyone use Raid or any of that type of program. Wouldn’t you just use a direct back up program on each disc. I get that there is no substitute for external back ups of critical data (not replaceable), I’m just looking for a stop gap against drive failure and the ability to rebuild that drive without ripping all my Blu-ray’s again. I keep hard copies of all the family photos etc. on disc and cloud as well as on my Plex. Now I’m really confused about what kind of rebuilding of a dead hard drive any of these programs provide. 

[trurl]

27 minutes ago, Rix001 said:

Now I’m really confused about what kind of rebuilding of a dead hard drive any of these programs provide.

Parity by itself cannot recover anything. The concept of parity is used in many ways in computers and communications. Parity is simply a bit that allows a missing bit to be calculated from all the other bits.

 

In the case of Unraid, all the bits of a failed or missing disk can be calculated using all the bits of the parity disk PLUS all the bits of all the remaining disks.

 

Parity isn't at all complicated, and understanding parity helps make other things about the operation of Unraid easier to understand. Here is the wiki on parity:

 

https://wiki.unraid.net/UnRAID_6/Overview#Parity-Protected_Array

[skaterpunk0187]

Your setup consists of Parity, Data1, Data2, and Data3. Any one of those disks can fail and can be replaced and rebuilt with the original data. Say the Data2 drive fails you put in a new drive to replace Data2, Unraid will use Data1, Data3, and Parity to rebuild Data2 back to its pre-failed state. Depending on the amount of data this rebuild could take several days to complete. The rebuild is a consistent read/write on all drives in the array, this puts a lot of stress on the other drives increasing their risk of failure. If your buying all drives at the same time to build the Unraid server they will all have the same amount of hours on them increasing failure risk. If you don't need all that storage to start with I would say start with one data and the parity and add drives as you need them (best feature of Unraid). 

[trurl]

A couple of nits to pick.

 

3 minutes ago, skaterpunk0187 said:

Depending on the amount of data this rebuild could take several days to complete.

If you have no controller bottlenecks, then rebuilding even an 8TB drive will probably not take more than a day.

 

4 minutes ago, skaterpunk0187 said:

The rebuild is a consistent read/write on all drives in the array, this puts a lot of stress on the other drives increasing their risk of failure.

Rebuild only reads from all the other disks, and only writes to the rebuilding disk.

[skaterpunk0187]

12 minutes ago, trurl said:

A couple of nits to pick.

 

If you have no controller bottlenecks, then rebuilding even an 8TB drive will probably not take more than a day.

Well that's good to know. I have not had the privilege of rebuilding a disk in Unraid. I've done it several times with a Synology box and they "detune" the rebuild to reduce the stress on the other drives. I figured Unraid would do something similar since they "detune" the write speeds of the spinning disks without configuring the tunables.

12 minutes ago, trurl said:

Rebuild only reads from all the other disks, and only writes to the rebuilding disk.

Thanks that's what I meant re-reading what I said it didn't come out that way.