Internal HDD Problem

prpr said:
It's not the files. It's the lower levels. What is the filesystem? How does the RAID work? And can you "just pull out the discs and attach them to a PC or another NAS" and expect it to work?
All these are unknown (to me). I don't know how a QNAP works and I didn't want to take the (expensive) risk of finding out and it possibly not working. Information on this never seems to be readily available. The manufacturers only want you to read the glossy blurb.
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Well I haven't looked into QNAP yet as the details are somewhat academic given that I cant afford one (!); however generally speaking you can format a NAS's hard drives with whatever format or RAID type you desire. There are I think four ways to arrange RAIDs. On my old ReadyNAS I went for the simplest which is mirroring one disc onto the other. Striping only gives benefits in high performance applications wherein you attempt to make speed gains by reading sectors in parallel from multiple drives. This is more suited to enterprise use than domestic video servers.
 
Steve7777777 said:
however generally speaking you can format a NAS's hard drives with whatever format or RAID type you desire.
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Yes, but is the RAID metadata of one manufacturer compatible with another? Or even with a different box from the same manufacturer's later (future?) products (when you can't get your original box any more and it's just blown up)?
 
prpr said:
Yes, but is the RAID metadata of one manufacturer compatible with another? Or even with a different box from the same manufacturer's later (future?) products (when you can't get your original box any more and it's just blown up)?
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If you are concerned about using RAID then you dont have to configure it. RAID isnt a substitute for backups either remember, everything on your NAS should be retrievable from backup thus bypassing any specifics of RAID/disk format.
 
Black Hole said:
You always lose about half your storage capacity with a RAID optimised for data security
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Ah yes, but I have configured my primary NAS as JABOD, as I backup my backups. Not 'off site' but to an unpowered (most of the time) mirrored NAS.
 
Steve7777777 said:
If you are concerned about using RAID then you dont have to configure it. RAID isnt a substitute for backups either remember, everything on your NAS should be retrievable from backup thus bypassing any specifics of RAID/disk format.
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Indeed, I once lost both drives in a mirrored RAID due to a power surge.
 
I use a Synology NAS to backup and centralise all my content. It's nearly reached capacity with 4TB drives but can be expanded via 2 additional expansion units. I'm using Synology's Hybrid RAID (SHR) so a hardware failure on the main unit would be a worry. Thankfully spare parts are available and in a worse case scenario I'd buy or borrow another Synology unit to recover the data.

EDIT: Looks like Synology does support recovery via a PC (see HERE)
 
This bit looks problematic:
Remove the hard drives from your DiskStation and connect them to your computer. For RAID or SHR configurations, you'll have to connect all the hard drives (excluding hard drives used as hot spares) to your computer at the same time.
Note: Please make sure the file system running on the hard drives of your Synology NAS are EXT4 or Btrfs.
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These issues are why I have already bought just one component of my prospective new super-duper workhorse PC: a Blu-ray writer with M-disc capability (I can hook it up to my existing notebook with a USB-SATA adapter).
 
I wonder whether that is for striping and Raid0? For Raid1, I see no reason why you would need all connected except if the diskstation is in the middle of mirroring.
 
You mean the need to connect all the drives at once? Other than for one pair of mirrored drives, the RAID schemes spread data and indexing across multiple drives - so it is no surprise that they all need to be present to participate in recovering data. The more drives there are in the array, the more difficult it will be to run them simultaneously - but I'm more concerned about the comment which seems to imply the disks may not be in a format compatible with the recovery utility (and what the heck is BTRFS anyway?).
 
Black Hole said:
I guessed that... never heard of it before.
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BTRFS is the future default Linux file system. It has similar attributes to Sun's ZFS and MS's StorageSpaces/ReFS. If you're interested in using it for a NAS, you might like to look at Rockstor (http://rockstor.com/) which provides an integrated NAS based on BTRFS, with similar capabilities to QNAP, Synology etc. It runs on commodity hardware.
The main outstanding issues with BTRFS at the moment are to do with providing reliable support for RAID5/6 in all fail modes. Otherwise it's solid. As with all such systems, its redundancy features are to improve availability in the face of hardware fails, not to provide backup.
 
Black Hole said:
You mean the need to connect all the drives at once? Other than for one pair of mirrored drives, the RAID schemes spread data and indexing across multiple drives - so it is no surprise that they all need to be present to participate in recovering data.
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The question from sceptic was about a two disk Synology NAS, with mirroring, so, as I said, connecting one drive might be sufficient.
 
Mike0001 said:
The question from sceptic was about a two disk Synology NAS, with mirroring, so, as I said, connecting one drive might be sufficient.
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To quote your previous remark:
Mike0001 said:
I wonder whether that is for striping and Raid0? For Raid1, I see no reason why you would need all connected except if the diskstation is in the middle of mirroring.
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I read this in the context of the general discussion of Synology recovery, rather than sceptic's specific case. In other words a general "you" rather than a specific "you".
 
My Synology NAS is a 5 disk NAS (using SHR) which is soon to be expanded to 10 (2 arrays of 5) via an expansion unit. Connecting 5 HDD's to my main PC would not be a problem as it already has 6 HDD's connected as a RAID 5 data partition which I could disconnect temporarily if required. The main issue to connecting multiple drives is probably going to be a lack of SATA ports, which can easily be resolved by fitting a SATA expansion card.
 
OMG, Raid and SATA Hell!

Someone mentioned that Raid is no substitute for backup. Even a combination of both is no substitution if you backup a screwed up version of your files. Delete all your files and a backup mirror of them will delete them on the mirrored Raid system too! At least Synology include a waste bin.
 
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