Can NAS be used as DAS?

[BennyC]

Hi guys,

My 1.5TB Seagate external is giving me the 'clicks of death' so I am in the process of sourcing some 1 or 2TB drives to use in 'Raid 1' to effectively replace this and save me the worry of ever having it fail on me again.

I've been trying to find a suitable enclosure and I then discovered NAS (I'm not very knowledgable on this area appart from what I've learnt last night!).

I was thinking I needed DAS but realised that at somepoint further down the line I might want to end up sharing this content over the network (when I move out/buy property/use multiple machines) and a NAS enclosure would be useful so I was wondering if NAS can also be used as DAS? so at a later date I could then hook this upto the network? So I could basically sit this on my desk and use it for Raid via USB for the meantime?

Thanks in advance,

BennyC

 

[marms]

It depends on the enclosure, some nas drives also have a usb port for direct connection to a single pc.

 

[JonJ678]

Raid 1 is good for avoiding downtime, but has some problems as far as data security goes. If you delete a file from one drive, it'll vanish from the other. Data corruption tends to infect both drives.

As an alternative, I'm very much in favour of having two disks of the same capacity, where one is in use and the other is a weekly (or daily) backup of the first. If robocopy or rsync is used the backup doesn't take much time, and if you delete a file(or partition table) by mistake there's a good chance it's still available on the other drive.

A network attached drive works much like any other one, except they tend to be slower.

 

[BennyC]

Thanks for the replies.

I decided that I don't really need NAS at the moment so will be sticking with a DAS enclosure. Most probably the Lian Li EX-50 when it becomes available.

Would you happen to know if it would automatically write to the second 'weekly backup' disc if I left it in the bay and just plugged it in as and when? Or would I need some software to initiate RAID1? I know there are master switches/jumpers on the back so I think changing these and attatching the other drive would probably do it?

 

[JonJ678]

The lian li box does look very good indeed. I particularly like avoiding any need for software, and the rated performance. I'm not sure how to check whether "the system must support Port Multiplier specification".

If set up as raid 1 (or possibly "clone"), you should be able to unplug a drive and have it continue as normal. When you later plug the drive back in, it should rebuild the array leaving you with two identical disks which both look like the newer version. How well this is implemented is difficult to judge.

I'm taking the simpler approach of calling rsync once a week to move data from the live drive across to the backup one. This works, but is not as elegant a solution as you're suggesting.

 

[BennyC]

Thanks for your replies, very helpful.

I'll do some testing. Set the Ex-50 up for Raid1 with both drives (Likely to be Samsung Spinpoint F4 EcoGreen 2TB's) and pop a few files on. Then I'll set the EX-50 to just standard extra drives (no raid) and check both are mirrored. After that I'll switch it back to raid and unplug one drive, pop some more files on and then replug the second drive back in and then check that both drives are mirrored.

I might have to leave the jumpers/switches just set to normal when just one drive is in and then switch them to RAID1 when I wish to clone to the second disk and then switch them back again when I'm done.

I'll take some pictures and pop a little mini review up for anyone else that's interested when it all arrives.