Advantages/Disadvantages of Synology Hybrid Raid?

[Grahamps]

I have a DS1511+ and five 3TB drives. Should I install all of these at once, whether I need that capacity immediately? Whether yes or no, does this amount of drives help determine the choice of SHR or RAID type?

Conceivably, I could need 12TB of storage before the impetus for this purchase/project is completed.

It looks like very high-minded people debate RAID choices. For music listening and home use, should I forego the debate and run with SHR? Is RAID 6 the alternative to SHR, in my case?

Peace and thanks,
Graham

[steagle]

Hey Grahamps, First of all, you won't get 12TB of usable storage with your 5x 3TB drives in any protected RAID array (despite what RAID calculators on the internet might suggest). For SHR+1 or RAID5, you'll lose one full drive to parity, and then you have to consider your 3TB drives are actually about 2.7TB, so I think you'll be closer to 10.5TB once the array is fully built.

As to what RAID method to go with, it all depends on how much protection you want for you data. Personally, in my experience (both as a home enthusiast and IT professional) I have never had two drives fail at the same time in a RAID array I've built. Nor have I had a second drive fail while the array was being rebuilt to a new drive I had just replaced. While it certainly is possible and has probably happened numerous times, I don't feel that the loss in storage is worth the extra protection, ynless we're talking mission critical, enterprise level applications (say a database server for a software development company that hundreds of people access 24/7). I think RAID5 or SHR+1 is fine for most situations, especially in 5-bay enclosures and below.

As for deciding between RAID5 or SHR+1, I think the clear choice is SHR if you plan to stick with Synology devices in the future (since it is proprietary) and if you plan to upgrade the hard drives at some point.

[eagleman]

Hi

Just wandering now if it is possible to go from Raid1 to SNR without loosing data?

I have migrated by moving my two 2TB disks from my old ds207+ to ds712+ Now everything is up and running in a raid1 configuration.

[HarryPotter]

The only way:

- shutdown, remove 1 HD, reboot
- shutdown, reinsert, HD, reboot
- create new SHR volume with HD
- move data from old, degraded volume to new volume
- delete old volume
- expand 2nd volume with 2nd HD
- enjoy

[fishhy]

I have 3 x 2TB drives running SHR (Raid 5) and two more 500GB drives running in a mirror.

Why can't I add both of the 500 GB drives and get at LEAST 500GB more? When they are not part of a disk group or volume they still don't show up to be added to the existing SHR (RAID 5) array.

For simplicity sake, I'd like to have them all under one volume or disk group.
Seems that it could at LEAST span the volumes (giving me 2 drives failover, 1 for the raid 5 and 1 for the RAID 0 but no such luck??

[maxxfi]

@fishhy: It cannot, because it doesn't fit with the way SHR works.
Check the wiki: http://forum.synology.com/wiki/index.ph ... id_RAID%3F
SHR works by taking an equal 'slice' from all HDDs. As you previously had 2TB disk, the first 'slice' from all disks has to be 2TB, and so the 500GB disks cannot be included in that configuration.

[sl2013]

Im not tech savvy, but can usually find my way around.
I just set up DS212, 2x2TB disks, with default SHR with data protection 1 disk tolerance.
Based on the thread, it appears it should essentially be like RAID 1.
SO
In disk management, it looks like I have 1 volume x 2TB. And it says nothing about the other disk except to say it is there and status is 'normal'. I assume this is usual.
BUT
I don't seem to have the option to change RAID config.
If I click on VOLUME tab, the only sub tab available is REMOVE. I try to click on anything in 'volume 1' with no luck.
The other tabs (CREATE, MANAGE, etc) are not accessable tabs.
Is there a reason?

I have the latest DSM and Assistant versions, if that matters.
Thanks.

[HarryPotter]

Yes there is a reason: your 2 HD are setup as SHR and thats it, there is nothing more to manage.

[maxxfi]

In disk management, it looks like I have 1 volume x 2TB. And it says nothing about the other disk except to say it is there and status is 'normal'. I assume this is usual.

It is also probably saying among the Properties of the volume something like "Type: SHR (with data protection of 1 disk)" and in the Disk Info section it should list both Disk 1 and Disk 2.
This means that both disks are already in use to make that volume: no resource available to Create a new volume or Manage (=extend) an existing one.

[eagleman]

The only way:

- shutdown, remove 1 HD, reboot
- shutdown, reinsert, HD, reboot
- create new SHR volume with HD
- move data from old, degraded volume to new volume
- delete old volume
- expand 2nd volume with 2nd HD
- enjoy

Thanks Harry

I'am testing this now on my old ds207? with old disks. Just some more questions.

Are there certain steps to think of when i want to make an exact copy by moving data from old, degraded volume to the new SHR volume ??

On a 2 disk Nas is there really a benefit to have SHR instead of a normal RAID1. I mean would it be easier to upgrade to larger disks later. Or if i later bought a DX510 to expand would it make any difference ??

Is it be possible to have the 2 disks in my ds712+ together with the disks in a DX510 and have it all in one volume ??

[coolspot]

As you previously had 2TB disk, the first 'slice' from all disks has to be 2TB, and so the 500GB disks cannot be included in that configuration.

What I don't get is why Synology doesn't define a smaller default slice - i.e. 500GB or 250GB; this way pretty much any drive size would work.

Or even better, prompt the user for the slice size configuration?

[maxxfi]

The system tries to find the biggest size that would fit all disks (at RAID creation time), because choosing anything smaller would bring lower performances.
If you have e.g. three 2TB disks, and 'slice' size is 2TB, SHR makes one RAID 5 of the three disks RAID5(3x2TB) and it's done.
If instead the 'slice factor' would force to be e.g. 500 GB in order to accomodate a smaller disk later, it would need to make four RAID 5 arrays, and chain them together RAID5(3x500GB)+RAID5(3x500GB)+RAID5(3x500GB)+RAID5(3x500GB).
Likely not a convenient proposition for most of the users. SHR is supposed to be the 'easy way to RAID' for people not too interested in technical details, so asking for parameters is probably not part of Synology plan.

If you really want to use your 500 GB, you do have a possibility, but you have to re-build your SHR from scratch.

[BenzOzzy]

Please excuse my ignorance, I am new to RAID and NAS in general.

I am in the process of setting up a DS212+ and 2x3TB WD green drives (WD30EZRX). The disks are still verifying in the background but the device is visible on my network.

After creation, Storage Manager shows the (SHR) volume available space at 2.68 TB.

My question is this; what do I do when the volume (2.68TB) is eventually full?

I presume that I remove one drive, store it somewhere safe and then replace it with a new one. I then reformat both of the installed disks and create a new volume...is it that simple or am I way off?

If I am correct how do I then access the data on the stored disk (mostly photo, movie, audio files)can I put it back into the device or what happens there?

I am sure its a silly question , but in this case Google has not been my friend.

[maxxfi]

My question is this; what do I do when the volume (2.68TB) is eventually full?

You can upgrade to bigger drives, e.g. with 4TB disks:
- remove one of the 3TB disks, replace it with a 4TB disk, resync the array
- remove the other 3TB, replace it with a 4TB disk, resync the array, then expand to use the extra 1TB from the news disks

Or, if you change NAS, e.g. you swap your DS212+ for a 4-bays DS412+:
- move the two disks to the 412+, resync
- add more disks (3TB or bigger) and extend the current volume, or create a new one

[BenzOzzy]

My question is this; what do I do when the volume (2.68TB) is eventually full?

You can upgrade to bigger drives, e.g. with 4TB disks:
- remove one of the 3TB disks, replace it with a 4TB disk, resync the array
- remove the other 3TB, replace it with a 4TB disk, resync the array, then expand to use the extra 1TB from the news disks

So does this ^^ just mean that the data on the WD3TB disks can be wiped and the drives used elsewhere like in another PC for example?

Or, if you change NAS, e.g. you swap your DS212+ for a 4-bays DS412+:
- move the two disks to the 412+, resync
- add more disks (3TB or bigger) and extend the current volume, or create a new one

I sort of regret buying the 2 bay over the 4 bay now, as I didn't research RAID enough I'd wrongly assumed I'd get the full 6TB of space(Lol)
Wife will have my nuts if I go out and bought the 4 bay now.. .

Thanks for the quick reply too.