RAID1 and NAS drives???

[Wing Commander Fowler]

Hi again Chaps - looking for a network drive for storage of media and would like 1TB capacity but also like the idea of having a mirrored backup. I have the choice of some 2 bay NAS enclosures which will accept two 1tb drives. Thes sometimes come with the appropriate backup software.

Do I have the option of RAID1 through a network at all? I am obviously a dummy regarding SATA drives and the RAID principle so please forgive me if this is all horsedoings.......

Any recommends on cheapish and quietish drives at all?

Many thanx - Fowler

[Saab Dastard]

WCF,

The NAS box presents its storage to a networked PC as a logical volume, irrespective of how the disks are configured in the NAS box. The networked PCs have no visibility of how the disk(s) in the volume are arranged.

If the NAS box accommodates 2 drives, supports RAID 1 and the operating system of the network clients (CIFS for windows - or the older SMB) that will access it then that's all you need.

SATA disks can be used in a RAID 1 configuration, either in hardware - i.e. at the disk controller level - or in software, i.e. at the operating system level. Depends on the NAS box.

Traditionally, hardware RAID was only implemented on SCSI controllers, because of the ability to address multiple physical disks - which the IDE Parallel ATA (PATA) interface didn't support - as you know, only 2 disks per IDE channel.

With the introduction of Serial ATA, an alternative to SCSI became possible.

SD

[Wing Commander Fowler]

Thanx SD.

So, if I read you correctly, it is possible for two seperate NAS enclosures each containing one drive can mirror. How would you know whether the nas enclosure was capable of this? What would the trigger terms be? Would you happen to know of any particular units that would manage this amazing feat?

OR should I bite the bullet and just go for one of these (http://www.dealzilla.co.uk/products/db00109t24uz-linksys-by-cisco-nas200-network-storage-system-with-2-bays/) or one of these (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=250335692224&ssPageName=STRK:MEWA:IT&ih=015) which is already kitted out as required?

Thanx again for your help and happy new year! :ok:

[Mac the Knife]

Combine an old PC with a couple of biggish drives (you can use a PCI SATA card if you need it) with FreeNAS (FreeNAS: The Free NAS Server - Home (http://www.freenas.org/)) and off you go.

Store your stuff on HDD0 of the FreeNAS server and set FreeNAS to do an rsync to HDD1 daily or weekly or whatever.

Easy, reliable and cheap.

:ok:

[Saab Dastard]

WCF,

So, if I read you correctly, it is possible for two seperate NAS enclosures each containing one drive can mirror.

No, you aren't reading me correctly - the disks must be in the same enclosure.

SD

[The late XV105]

The four-level backup strategy for my home media server uses the latest version of Memeo Backup to run multiple backup plans to multiple HDDs. It works beautifully, syncs perfectly when an off line disk next comes on line, and came bundled with a 1TB eSATA Seagate Freeagent Pro that forms the "semi off site" part of the strategy; configured for hot (un)plugging, I physically disconnect it, put it in a sealed tupperware box whilst still warm, and take it out to the garage (separate outbuilding) whenever the house is unoccupied.

In terms of reliability whatever the season and two test restorations of data this has worked fine, but given my success with Netgear HDX101 ethernet-over-mains homeplugs, I wish to switch to my original idea of placing a NAS in the garage instead. Far handier than having to do the above shenanigans and it'll free up another 1TB of much needed space too.

Although on a separate ring to my HomeHub router, testing with one of my HDX101s shows that I never get less than 50Mbps (Tx and Rx) in the garage and usually nearer 100Mbps. My question is therefore "which NAS will give me the most reliable and cost effective performance when configured as a two bay (or four bay depending on cost differntial) RAID 1 backup device?"

Guessing that whatever I buy will come with empty bays, my intention is to fit either one or two pairs of 1TB Seagate Barracuda HDDs for the aforementioned RAID 1 configuring.

Usage will be purely as the "semi off site" part of my backup strategy. No streaming. No need for remote access. No need for hot swapping. No nothing.

I am open minded when it comes to NAS o/s flavour and don't mind learning something new.


TVM

[Jofm5]

The NAS box presents its storage to a networked PC as a logical volume, irrespective of how the disks are configured in the NAS box. The networked PCs have no visibility of how the disk(s) in the volume are arranged.


A bit of a sweeping statement Saab, most NAS' can be partitioned into logical volumes and some even support iSCSI for mounting of remote disks locally (ideal if your using something like SQL Server which typically will not allow installation of database devices on remote disks) - these are stored as preconfigured files on the NAS.

As for disks, The Seagate barracuda is a good drive as is the Samsung Spinpoint F1 (which is benchmarked slightly quicker but your constraint will be the network not the drive). Either will do and the price is virtually the same (a quick google threw up the F1 £1 cheaper at £56) so not much in it.

Personally for speed I would install two drives mirrored in my local machine and then get an eSATA external drive for backing up which can then be removed off site (eSATA giving you similar speeds externally than externally but cannot be used over great distance).

[The late XV105]

Hi Jofm5,

Not sure if your post entirely relates to SD's or not, but in case the latter part relates to mine; as mentioned I already have an eSATA approach that I take semi-offsite*, but I want to use ethernet-over-mains and a NAS as a more convenient alternative. Within reason (and my 50Mbps is fine), performance is a non-issue.

If your post does relate to SD's, then ignore the above! :)

*The fully off-site part of the strategy involves two 500GB USB HDDs that are swapped on rotation.

[bnt]

For the sake of simplicity and performance, you generally want to see RAID in hardware, and that effectively hides the details from the end user, whether the RAID volume is local or networked. Once the RAID is configured, the OS sees a single virtual disk, and that's the end of it

It is possible to do it in software, of course, using Windows Disk Manager, or particularly if using Linux (which FreeNAS is based on). The question changes from "can you do it?" to one of "would you want to do it"? Using LVM (http://en.wikipedia.org/wiki/Logical_Volume_Manager_%28Linux%29), you can create RAID volumes from local or remote volumes, or even mismatched volumes e.g. a local disk and an iSCSI volume.

[Mac the Knife]

Once again, I urge anyone who needs anything like this to consider Olivier Cochard-Labbe's "FreeNAS" - FreeNAS: The Free NAS Server - Home (http://www.freenas.org/)

This is a fully-fledged NAS application running under BSD Unix and getting better all the time. The versatility and flexibility of this NAS server is phenomenal.

I use it for office backup. Booting from a USB stick and using rsync the NAS runs a silent incremental daily backup of each of 8 people in the office, each to their own directory, accessible only to them on HDD1. It does a weekly rsync to HDD2 and a monthly rsync to HDD3.

Administration is through a very well crafted Web interface.

Makes yer average NAS box look like a kids toy.

:ok:

Mac