Thoughs on RAID 1

[Marshall]

Hi,

I have always been told by the IT Company that supports our server that you must have at least Raid 1 along with a form of backup been tape or an External drive.
So I have been looking for a NAS to work as a Central storage for two computers, keep in mind the NAS must have a USB port for an External Backup and the NAS also has to have RAID 1.
The trouble is I can't find to many NAS units that have RAID 1.
Western digital has the My Book world edition (Single Drive) Seagate has Freeagent (Single Drive) and Maxtor has the Central Axis (Single Drive) the only one I have found is the Lacie 2big, which looked great until I read reviews on it, and it seems there are a lot of disappointed Lacie customers.
I have found the Synology and QNAP NAS products, but these require you to purchase the drives separately which gets to expensive.
So what are your thoughts on RAID 1, do you really need RAID 1 or is a Single drive NAS enough with a external backup drive and software to sync.
Maybe even if you have two USB ports you could try and mirror the drive.

Would to know what your thoughts are on RAID 1.
Thanks

 

[thiggins]

There are plenty of RAID 1 products available, both with and without drives. Synology, QNAP and Thecus BYOD (Bring Your Own Disk) products are relatively expensive. But that is because they support many features that you probably don't need.

USe the RAID 1 NAS Chart to find more products. Other options include the NETGEAR ReadyNAS Duo, Iomega ix2, Linksys MediaHub and more.

RAID 1 is not essential, but backup is. RAID 1 helps insure against drive failure. It does not help you, however, if the NAS power supply or controller dies unexpectedly.

If you are doing backup to an attached drive, you should have at least two drives and alternate them, storing one offsite or in a fireproof safe.

Also see Smart SOHOs Don't Do RAID.

 

[Steven]

More RAID1 questions

The more I know, the more difficult it gets to choose what to buy (or build)... So here are a few more questions.

Let me first state what my goal is: to have a place on the network where I can store files (in order to un-burden our laptops), and which I can easily back up. It will hold primarily pictures and movies, and some work files. I am still looking for an easy background back-up software, so that my partner doesn't have to worry about all this tech. Access from other places (web-based or ftp) would be great. If the machine could run backup jobs to web-based services, that would even be better.

Now, if I buy a box with room for 4 disks, insert 2 disks and set it up for RAID1:

- Will I be able to add 2 more disks later without having to export / import data and still have it as one mirrored volume?

- I had a brainwave to do back-ups by swapping out a drive (a 3rd or 5th identical one). That way, the drive I take out has all the data, while it all copies to the new drive. I can do that, say, once a week. Is that feasible, or do the drives get formatted and re-built again every time you change them? Is there another mirroring solution that can do that better?

- If the whole hardware dies, can I take out the disk(s) and read them on another machine? Or, again, is another mirroring technique better for that.

I should probably just buy what is on offer in a shop. Then again, I once picked up a Buffalo Linkstation 250 on an impulse, and I don't trust this one-disk solution. Better to have something I understand and can rely on.

 

[thiggins]

- Will I be able to add 2 more disks later without having to export / import data and still have it as one mirrored volume?

I have not seen consumer NASes that support RAID 1 for more than two drives.

- I had a brainwave to do back-ups by swapping out a drive (a 3rd or 5th identical one). That way, the drive I take out has all the data, while it all copies to the new drive. I can do that, say, once a week. Is that feasible, or do the drives get formatted and re-built again every time you change them? Is there another mirroring solution that can do that better?

You might be able to do this by pulling one drive of a RAID 1 array, then inserting another drive an letting it resync. But resync takes time and you are risking losing data if the other drive dies or there is a glitch during rebuild. Better to leave the RAID array intact and backup to an external or networked drive.

- If the whole hardware dies, can I take out the disk(s) and read them on another machine? Or, again, is another mirroring technique better for that.

You could do this if you have an empty chassis of the same product.

I should probably just buy what is on offer in a shop. Then again, I once picked up a Buffalo Linkstation 250 on an impulse, and I don't trust this one-disk solution. Better to have something I understand and can rely on.

You should not trust your data to any single device, RAID or not. All you would need to do is get another Buffalo LinkStation and use its built-in backup utility to do automatic, scheduled NAS-to-NAS backups.

 

[Steven]

Many thanks for these answers! I think I am beginning to see the light (finally, one might say).

My current instinct is to leave RAID alone and go toward another solution to copy / mirror data. Windows might do just fine for that, but then I will need to build a box, I guess.

Back to the "build your own Atom NAS" discussions then

 

[axxe]

Glad I stumbled on this thread!

I had no idea I couldn't use RAID1 with a 4-disk array (nesting RAID0 under RAID1 to make 4x500G disks into a 1TB RAID1).

I also mistakenly assumed I could pull a disk from a RAID1 array and read files off it by installing it in another enclosure, meaning the data in a RAID1 array could survive a controller/PS failure.

Now here's my question: You say "You should not trust your data to any single device, RAID or not. All you would need to do is get another Buffalo LinkStation and use its built-in backup utility to do automatic, scheduled NAS-to-NAS backups.", but in Smart SOHOs Don't Do RAID you give the Buffalo LinkStation as an example of a NAS that CAN'T backup except over USB. What am I missing?

I guess then what I'm looking for is a ~2TB NAS with very fast file copy and good scheduled NAS-NAS backup...

 

[thiggins]

I had no idea I couldn't use RAID1 with a 4-disk array (nesting RAID0 under RAID1 to make 4x500G disks into a 1TB RAID1).

Actually, you can combine 4 drives using a combination of RAID 0 and 1 with products that support RAID "10". Thecus and Buffalo four-drive NASes support RAID 10 (among others).

I also mistakenly assumed I could pull a disk from a RAID1 array and read files off it by installing it in another enclosure, meaning the data in a RAID1 array could survive a controller/PS failure.

You can certainly pull a drive from a good RAID 1 array and read it in another system that supports the format that the drive is written in. But if you pull a drive from a failed array, you may or may not be able to read it, depending on how the array failed.

Now here's my question: You say "You should not trust your data to any single device, RAID or not. All you would need to do is get another Buffalo LinkStation and use its built-in backup utility to do automatic, scheduled NAS-to-NAS backups.", but in Smart SOHOs Don't Do RAID you give the Buffalo LinkStation as an example of a NAS that CAN'T backup except over USB. What am I missing?

The NAS in the article is an original LinkStation. All current Buffalo NASes support attached and NAS-to-NAS backup.