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NAS aggregation

iamnemo

Junior Member
Hi! I have half a dozen D-Link DNS-323 NAS units in my home network. I would like to see them as a single file system in XP (NAS aggregation or virtualization).

What are my options for doing that (preferably software only). Thanks!
 
Looks like an ARM device running Linux and I see instructions for putting Debian on it, although it looks pretty involved. While I can think of a few ways to do what you want, they all require Linux experience on top of whatever's required to make changes on one of the devices.

The simplest would be to choose one as the entry NAS, get into it and just mount the other's shares via CIFS into it's share root. They'd still be separate directories below the main share but it would be a single tree to mount on your XP machine.

If you wanted to get crazy you could use nbd to bring the secondary NAS's drives over to the main one as block devices and then use software RAID or LVM to combine them and share that from the main NAS. That would get you one big drive but it would be a lot more fragile.
 
Originally posted by: Nothinman
Looks like an ARM device running Linux and I see instructions for putting Debian on it, although it looks pretty involved. While I can think of a few ways to do what you want, they all require Linux experience on top of whatever's required to make changes on one of the devices.

The simplest would be to choose one as the entry NAS, get into it and just mount the other's shares via CIFS into it's share root. They'd still be separate directories below the main share but it would be a single tree to mount on your XP machine.

If you wanted to get crazy you could use nbd to bring the secondary NAS's drives over to the main one as block devices and then use software RAID or LVM to combine them and share that from the main NAS. That would get you one big drive but it would be a lot more fragile.

Would note that is likely would be slow. Mostly because all the data from the other units would need to flow through the main unit then to the PC. That unit while neat it not exactly brimming with CPU horse power.
 
If there is a way for it export an iSCSI target, you might be able to use software raid or JBOD mode. This also would be slow as the computer would need to talk to all 6 units at the same time via ethernet. Not sure if the iSCSI initiator can do RAID however so don't know.

Your basically working with a cheap soho NAS, NAS aggregation is a pretty high level "enterprise" feature that I don't see much or at all in the sub $70,000 NAS units. I would be cheaper to by a larger NAS unit and toss the 12 HDD's in that.
 
If there is a way for it export an iSCSI target, you might be able to use software raid or JBOD mode. This also would be slow as the computer would need to talk to all 6 units at the same time via ethernet. Not sure if the iSCSI initiator can do RAID however so don't know.

iSCSI just does block level access, once they're connected they'll show up in disk manager and you can do whatever you want. Unless MS added some odd restrictions of their own.
 
Originally posted by: Nothinman
If there is a way for it export an iSCSI target, you might be able to use software raid or JBOD mode. This also would be slow as the computer would need to talk to all 6 units at the same time via ethernet. Not sure if the iSCSI initiator can do RAID however so don't know.

iSCSI just does block level access, once they're connected they'll show up in disk manager and you can do whatever you want. Unless MS added some odd restrictions of their own.

The RAID software on Windows can be told that a certain devices are not "RAIDable." That is why you can't do RAID 5 of a bunch of USB sticks on certain systems. Same thing with 3.5 inch floppies etc. Linux doesn't have this restriction so you might be able to do it.

PS I would imagine this would be very CPU intensive also. iSCSI is basically an emulated device (ie software run) running software RAID on top of it might tax certain systems. Also performance might be limited without 2-3 gig ethernet ports to split the load on.
 
Originally posted by: Nothinman
iSCSI just does block level access, once they're connected they'll show up in disk manager and you can do whatever you want. Unless MS added some odd restrictions of their own
Windows software RAID with Microsoft's iSCSI initiator seems to work. I just created two 3 GB virtual disks with the free StarWind iSCSI target, running on a virtual Server 2008. Then I used Microsoft's iSCSI initiator (in Windows 7 RC) to make them dynamic disks and then created a software-RAID 1 (mirrored) drive on the Windows 7 RC machine. Seems to work fine.

Edit:
I was also able to create a striped (RAID0) and spanned (JBOD) array using those two iSCSI virtual disks. I only had two virtual disks, so I wasn't offered the option to create a RAID5 array.
 
Originally posted by: imagoon
Heh, learn something new everyday. How was the performance?
I was just thinking about measuring that.

HOWEVER, some bad news from StarWind's FAQ:

Q. I use dynamic disks with the remote storage. Every time I reboot my Windows
2003 server the volume shows a FAILED status and I have to REACTIVATE the disk
in order to use it. How can I fix this? If I use basic disks then I get killed
by the 2 TB limit.

A. It's common Windows problem (network stack starts much later in comparison
with the disk stack). Use basic disk to have 100% working installation. You
can also try to format the device as GPT disk instead of dynamic one. GUID
Partition Table is available since Windows Server 2003 SP1 and is known as
working well with remote storage (iSCSI, AoE, etc). There is no 2TB limit for
GPT disks.


Not an iSCSI issue per se, but obviously a big concern.

Edit:
I did a quick HDTune 2.55 and some actual file copies across my Gigabit network. I get around 30 MB/sec HDTune and about 22-30 MB/sec when copying a 4 GB file from Win7 to a 6 GB striped (RAID0) iSCSI array. But this could be as much network-dependent as disk-dependent. I'm using low-end networking hardware and am writing to a virtual server.

Oh, and I tried rebooting my Windows iSCSI server once. It worked fine, but that's hardly a definitive test.
 
Originally posted by: RebateMonger
HOWEVER, some bad news from StarWind's FAQ:

Q. I use dynamic disks with the remote storage. Every time I reboot my Windows
2003 server the volume shows a FAILED status and I have to REACTIVATE the disk
in order to use it. How can I fix this? If I use basic disks then I get killed
by the 2 TB limit.

A. It's common Windows problem (network stack starts much later in comparison
with the disk stack). Use basic disk to have 100% working installation. You
can also try to format the device as GPT disk instead of dynamic one. GUID
Partition Table is available since Windows Server 2003 SP1 and is known as
working well with remote storage (iSCSI, AoE, etc). There is no 2TB limit for
GPT disks.
On the other hand....from the "StarWind iSCSI Best Practices" dcoument:

"The easiest way to provide fault-tolerance to important application data is by using RAID-1 (mirroring) functionalities. StarWind is fully capable of handling any RAID configurations supported by Windows (Software RAID) or dedicated hardware RAID controller."

I don't know which is correct.
 
Originally posted by: RebateMonger
Originally posted by: RebateMonger
HOWEVER, some bad news from StarWind's FAQ:

Q. I use dynamic disks with the remote storage. Every time I reboot my Windows
2003 server the volume shows a FAILED status and I have to REACTIVATE the disk
in order to use it. How can I fix this? If I use basic disks then I get killed
by the 2 TB limit.

A. It's common Windows problem (network stack starts much later in comparison
with the disk stack). Use basic disk to have 100% working installation. You
can also try to format the device as GPT disk instead of dynamic one. GUID
Partition Table is available since Windows Server 2003 SP1 and is known as
working well with remote storage (iSCSI, AoE, etc). There is no 2TB limit for
GPT disks.
On the other hand....from the "StarWind iSCSI Best Practices" dcoument:

"The easiest way to provide fault-tolerance to important application data is by using RAID-1 (mirroring) functionalities. StarWind is fully capable of handling any RAID configurations supported by Windows (Software RAID) or dedicated hardware RAID controller."

I don't know which is correct.

I would guess they mean the system starwind is running on. IE starwind itself just exports the LUN. It is up to you to put it on a RAID disk or not (meaning the virtual disk file it makes.)
 
Thanks to everyone for all this valuable information!

Here are some more details:

My setup:

I have six (6) DNS-323 (v1.07 firmware) and a XP Pro computer connected to an 8-port unmanaged gigabit switch which is itself connected (for internet access) to my router (WRT54G) which is the DHCP server for my network.

Everything works fine except for the "wake-up" problem mentioned below.

Now my question is
:

I would like to see the six DNS-323 units as a single file system in XP Pro, i.e. one drive letter with each NAS as a folder under root. I believe this is known as NAS/file aggregation/virtualization.

What are my options for doing that (preferably software only). Thanks!

Wake-up problem:

Sometimes one of the DNS-323 doesn't "wake up" when accessed and I have to reboot it.

Thanks! Iam
 
Originally posted by: iamnemo
Thanks to everyone for all this valuable information!

Here are some more details:

My setup:

I have six (6) DNS-323 (v1.07 firmware) and a XP Pro computer connected to an 8-port unmanaged gigabit switch which is itself connected (for internet access) to my router (WRT54G) which is the DHCP server for my network.

Everything works fine except for the "wake-up" problem mentioned below.

Now my question is
:

I would like to see the six DNS-323 units as a single file system in XP Pro, i.e. one drive letter with each NAS as a folder under root. I believe this is known as NAS/file aggregation/virtualization.

What are my options for doing that (preferably software only). Thanks!

Wake-up problem:

Sometimes one of the DNS-323 doesn't "wake up" when accessed and I have to reboot it.

Thanks! Iam


2003 server can do this using DFS.

Again, if they do iSCSI you can use this:

http://support.microsoft.com/d...b;en-us;307889&sd=tech

The wake ups however will break your setup so you will want to fix that first.
 
The simplest and most reliable way to combine those disks would iinvolve putting them in a single case and running an operating system that combines the drives into a single array. Windows Home Server does that. FreeNAS will doubtless do it, too (but I've never used it).

With WHS, you'd move the content of one drive to free it up. Then install WHS on that drive. Then free up another drive by moving its data to WHS. Then add that drive to WHS' storage pool. Keep moving data and freeing up hard drives until they are all in the WHS storage pool and all the data is on the WHS.
 
To summarize and share what I have learned so far from different forums, here are my options to aggregate several NAS units together:

1) move all the drives (12) to the same Linux box and run some software NAS on them;

2) move all the drives (8 max) to a bigger NAS such as the QNAP TS-809 Pro Turbo 8-bay NAS which seems nice for under $2k; anyone knows of larger (and less expensive) ones?

3) flash some 3rd party firmware in my DNS-323 NAS so that they can become iSCSI initiators (or is it targets?);

4) use one of the NAS to mount the other shares via CIFS;

5) use StarWind server (http://www.starwindsoftware.co...wind-server-iscsi-san) to create a software SAN on a Windows box;

6) somebody suggested GlusterFS (http://www.gluster.org/docs/index.php/Main_Page) which seems to be a clustered file-system that aggregates various storage bricks over TCP/IP interconnect. Has anyone ever used that one?

7) use a hardware file virtualizer such as the F5 ARX series (http://www.f5.com/products/arx-series/) to control all other storage units. This is a really neat idea but this system costs $$$$$.

8) An interesting presentation about Storage Virtualization (http://www.snia.org/education/..._Virtualization_I.pdf) . Many other interesting tutorials too: http://www.snia.org/education/tutorials

Why don't anyone sell a smart gigabit switch that would aggregate all the storage units (NAS, PCs, etc.) connected to it? Any computer, PS3, SqueezeBox, etc. in the network would see the switch and its virtual file system. Is it a dumb idea or what?

 
If you decide to involve Windows Software RAID in SPANNED mode, be aware that if any of your spanned disks fail, ALL of the data on ALL of the spanned disks will be lost. Windows does not have any way to simply replace the failed drive and get the rest of your data back. I imagine that most of the data on the still-functional disks can be recovered, but not with any standard Microsoft tools.
 
Thanks for the warning RM. I learned the disadvantage of spanned and of striped disks under NT the hard way several years ago. Never again.

I would like the different disks just to appear to be part of the same file system, you know: each disk would be a folder under some common root.
 
Why don't anyone sell a smart gigabit switch that would aggregate all the storage units (NAS, PCs, etc.) connected to it? Any computer, PS3, SqueezeBox, etc. in the network would see the switch and its virtual file system. Is it a dumb idea or what?

Because that's not a switch's job. And at that point you've just recreated the thing you mentioned in #7 I think.
 
Originally posted by: iamnemo
I would like the different disks just to appear to be part of the same file system, you know: each disk would be a folder under some common root.
If the disks were made local (I think that's a requirement), then this sounds like Volume Mount Points in Windows or whatever its equivalent is in Linux.

Some more info.

As mentioned earlier, this is what DFS does with network shares.
 
Originally posted by: iamnemo
RM: the disks would indeed need to be local :-( But this method would work. Thanks!
If it's not clear in the links, Volume Mount Points work in Win 2000, XP, and Vista, as well as Windows Server OSes. You just have to be working with NTFS.
 
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