What RAID choice did you make?

[JTBurton]

I've done a lot of reading about RAID, but come to no conclusion.

As I'm about to buy a DiskStation (probably 410j, or maybe 411j if it comes out soon), I'll have to choose soon.

JBOD - biggest capacity but if one disk dies I lose the lot (is that right?)
RAID 1 - a bit faster (?) and guards against a disk failure at the expense of losing a disk's capacity
RAID 5 - no performance gain, but guards against a disk failure at the expense of losing a disk's capacity

Any advice?

Also, what is your main use? For me it is likely to be backup of 3 PCs, but I also find the media features attractive. In which case, how do I backup the NAS except with another NAS? Can I backup the NAS media folders to the NAS itself, which is a bit of a crappy strategy.

Trevor

[NomadicTendancy]

I use my DS as a Media server for my home network..Pictures, Video and Music

When I first purchased my DS 209 I chose to go with 2 volumes over 2 physical drives. The reason being, I had no external backup at the time and this setup seemed more reliable than using a RAID 1 configuration.. I was simply backing up volume 1 to volume 2 on a daily basis..

Now that I have an external backup source, I am changing to a RAID1 configuration only because it seems easier to recover from a Single Disk failure. Plus I will have an external backup in case the RAID becomes corrupted or in case of a Failure with the DS itself..

JBOD makes no sense to me..
If you span a larger volume over multiple disks with JBOD, if something goes wrong with a single disk you lose all of the data across all disks.. Why not leave each disk as its own volume and isolate the failure and possible data corruption to each disk? In other words why lose all of your data just because one disk crapped out?

RAID1
This is the setup I am currently upgrading to.. Only benefit I find from this setup is the ability to easily recover from a singe drive failure.. Just replace failed disk and let the RAID rebuild.

RAID5
If I had your setup (my ds only supports 2 disks) I would run a RAID5 and backup to an external storage device on a regular basis..Just like RAID1, its easy to recover from a SINGLE drive failure.. However, If you lose more than one Disk in a RAID5 setup, you are still SOL so its very important to back up your data..

I am by no means a Disk Storage guru.. so please correct me if I am wrong

[JTBurton]

That makes a lot of sense. I didn't realise you could do two volumes in a DS.

Thanks!

[csimon]

JBOD - biggest capacity but if one disk dies I lose the lot (is that right?)
RAID 1 - a bit faster (?) and guards against a disk failure at the expense of losing a disk's capacity
RAID 5 - no performance gain, but guards against a disk failure at the expense of losing a disk's capacity

Any advice?

As stated above. Some people regard RAID as a red herring and that it's completely over the top for home use. However, I certainly want as little hassle as possible in recovering from a failed disk or unit.

Also consider the Synology Hybrid RAID format, also called "Standard", as this will be presented by default I tink in models with more than 2 bays. The disadvantage of the above RAID formats is that your capacity is restricted to the size of the smallest disk. This is not a major problem with 2 disks in RAID 1, however if you've got 4 disks in RAID 5 and you decide you need to increase your capacity, you have to replace ALL of your disks with bigger ones before you gain anything. SHR uses a combination of RAIDs to provide multiple partitions, but it is completely transparent and it just looks like you've got one volume. But with SHR, you benefit immediately by increasing the size of just one disk. SHR will maximise the use of the disk space that you have available. The disadvantage is a 10% loss in performance.

I currently have a DS209 with two 1TB disks in RAID 1. This is intended to be a dedicated backup server, to back up the contents of my 2 PCs, also my media files. RAID 1 might be over-the-top for a backup device, but what happens if you need to retrieve a file from backup and then find your backup disk has crashed? Not hugely likely to happen, but can you afford to take the risk, it's a choice only each individual can make!

I'm also toying with the idea of a 4-bay NAS which will be an always-on device, for serving media files and perhaps for general network storage, moving My Documents from the PCs onto it for example. I will start with 2 disks in SHR (I want SSDs...), then add more when prices drop and capacities increase. If one disk fails, then I can simply replace it without having to restore from the backup server - as the last backup might not be current enough. Note that a single RAID system like this does *not* safeguard against accidentally deleting files or corrupted files.

So data security/safety has two considerations:

1. Availability of data and not losing *current* data if a disk fails. This implies a main filestore in some sort of mirrored configuration, i.e. RAID.
2. Ability to go back to any backup in the past to restore lost or corrupted files. This probably implies a separate backup device from your main filestore to which you back up at regular intervals.

In which case, how do I backup the NAS except with another NAS? Can I backup the NAS media folders to the NAS itself, which is a bit of a crappy strategy.

Yes, you can do this, but as you've realised it's not *completely* foolproof. If the RAID fails, or the unit fails and corrupts the data and is not recoverable, you've lost everything. With a 2-NAS strategy, you've lost your current data but at least can restore from the most recent backup.

[maxxfi]

SHR will maximise the use of the disk space that you have available. The disadvantage is a 10% loss in performance.

I'd rather say "disadvantage is up to 10% performance loss" to avoid that the 10% becomes a mythical number cast in stone.
As the "loss" is due to some extra layer of software, and CPUs are getting faster, and drivers optimized, I believe that this
factor is going to be lower and lower in current and future models, compared to the time when that statement has been made.

[manfredell]

Actually I tested Raid5 against SHR on my DS1010: I could not find any difference writing/reading or it was negligible

[VernonAMiller]

Standard, RAID 5. I have five identical-sized drives in my DS1010+ so it was the most natural choice, given my application.

Having worked on RAID products for lo these many years, I read the description of how SHR works and it looks pretty clean. I mean, sure, you might take some performance hit for SHR, depending on how things happen to get placed, but it's a great solution for those that don't happen to have a batch of identical drives.

Vernon