Do I RAID or not?

PaulCa

PaulCa

PaulCa

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3 May 2018
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I'm creating a new quieter and lower power mini-server for home use. It's mostly "single user".

It:
* Has bulk storage, movies, mp3s, etc. etc.
* Runs my home automation services in docker.
* Runs PiHole and Home Assistant

The server I have created (replacing a power hungry ex-gaming PC), is a Dell Optiplex i5 3.4Ghz, 8Gb RAM. I have a 256Gb Sandisk SSD as a boot drive.

I attached a 5 bay USB3.0 enclosure to it.

The plan was to put 3x2Tb drives in RAID 5. My existing 6Tb bulk storage drive and another existing 2Tb drive in the enclosure.

I've got to the point of initialising the RAID 5 array and I'm getting cold feet.

It turns out that 3x2Tb drives in RAID5 comes down to only 3.4Tb actual storage after formating.... and the array is STILL recovering and claiming to take 5 hours.

The concept was to store most personal work related stuff and personal "important" stuff on the RAID array. Probably my /home directory actually. Leaving the replaceable media stuff on the bulk drives.

In addition I have another external enclosure with a 2Tb drive in it which can be switched off. I use this for manual backups periodically. So selected "Must not lose" items would be transfered onto there as often as I remember, but the HDD itself will be powered off 95% of the time, so should last quite a while.

As I see it...

Reasons to have RAID5 - A small amount of resilience and recovery for one disk going bad. A small performance boost on reads.

Reasons not to have RAID 5 or at all - Adds complexity to recovering hard disks, especially when transfering between machines., lowers the amount of available space significantly. I get just over half of the capacity of the 3 disks.

What say ye?
 
A three drive RAID5 array will have the combined capacity of two of the drives, the third goes to parity. The other apparently lost space is the usual difference between Gigabytes (GB) and Gibibytes (GiB).

With 2TB drives, RAID5 is still a viable option. The rebuild times won't completely insane like they can become with larger drives. What I wouldn't personally like in that setup is the USB connection to the drives.

I run Unraid on my server/NAS. It still uses a version of parity RAID, but without many of the downsides of RAID5.
 
Yea the USB enclosure is less than ideal. I do have the option of a SATA PCIe card and running the cables out the back into another enclosure. Not right now though.
 
What OS are you using?

You'd certainly be better off using a SATA card/enclosure rather than USB where any kind of RAID is involved. (SAS would be ideal, but enclosures tend to be expensive)

Depending on what your goals are you might be better off with just a RAID1 of two 2tb drives for anything important, and then use the other 2TB for "expendable" data.

Alternatively as well as unraid that has been mentioned, if using Windows you could use https://stablebit.com/DrivePool/Overview to pool drives, and offer duplication of essential files (or even Windows Storage Spaces if you are brave)
 
Yea. I am thinking of just using 2 in RAID1 for important stuff and maybe a combo of ZFS and LVM for the remaining 2x2Tb disks to make one 4Tb.

I'm using Ubuntu on this machine.
 
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