Netgear ReadyNAS Duo Reviewed

[thiggins]

The ReadyNAS Duo brings most of the extensive ReadyNAS feature set to a lower-cost dual-drive compact NAS. [article link]

 

[Unregistered]

Netgear Readynas Duo - proprietary filesystem?

After reading the very positive review here on the Netgear Readynas Duo, I was considering purchasing one to replace my current NAS (WD Netcenter, unfortunately), however, I later read that the Readynas Duo (and MV+) use a "proprietary" filesystem (ext3 with 16k blocks) that would not be able to be read by any x86-based hardware. If that is true, it would mean that you'd be SOL if then Readynas hardware itself died, short of buying a new Readynas (if they are even still sold at that time). Can you confirm whether this is the case? Wouldn't I be better off with NAS that uses a standard filesystem that could allow emergency data recovery on standard PC hardware if needed?

 

[thiggins]

After reading the very positive review here on the Netgear Readynas Duo, I was considering purchasing one to replace my current NAS (WD Netcenter, unfortunately), however, I later read that the Readynas Duo (and MV+) use a "proprietary" filesystem (ext3 with 16k blocks) that would not be able to be read by any x86-based hardware.

This is the response I received from Netgear. The file system used by the ReadyNAS is EXT3.

Every new volume created with RAIDiator 4 will have 16KB block size. If the volume was created with RAIDiator 3, it will have a 4KB block size. Existing volumes with 4KB block size will not be touched during upgrade from RAIDiator 3 to 4, so it will always be 4KB if it was created with RAIDiator 3.

Only architectures that can read 16KB page sizes will be able to mount a volume created under RAIDiator 4. This includes SPARC (used by the ReadyNAS) and ia64. x86 systems (and x64) only support 4KB page sizes, so they cannot read them.

Some users on the forum have manually created the volume using a 4KB size using RAIDiator 4. You can find that info here: http://www.readynas.com/forum/viewtopic.php?p=114404#p114404

 

[wonmoi]

The article seem to suggest that you are not able to easily recover or read your data from a regular computer using the disks from a ReadyNas Duo which had suffered a crash.
So what is the benefit of having a ReadyNas Duo in RAID 1 if it is so difficult to recover data if the NAS crashes instead of the disks?

 

[Bill321]

The article seem to suggest that you are not able to easily recover or read your data from a regular computer using the disks from a ReadyNas Duo which had suffered a crash.
So what is the benefit of having a ReadyNas Duo in RAID 1 if it is so difficult to recover data if the NAS crashes instead of the disks?

Just my two cents: I would never rely on any Raid - even Raid 1 - as the only storage for important data. I've been burned too often. If the hardware fails, it can easily corrupt both disks (no matter what filesystem is used on the disks.) Plus, even if only one disk is gone, it is very easy for operator error to ruin the data on the remaining disk. And, Raid 1 does nothing to prevent the accidental deletion of important files (probably the most likely scenario for losing data.)

Raid improves uptime (continued online access to the data). It does not provide disaster prevention.

Of course, I am paranoid having learned the hard way - I now keep two complete local backups using separate systems of all important data (using rsync on each machine running 12 hours apart). With the info available on the net (mostly on this site), it isn't that hard to setup, and with wake on lan and automatic shutdown in the scripts, it doesn't add too much to the energy bill.

Plus, I have an off-site backup of the really critical stuff.

Bill

 

[wonmoi]

Thanks Bill for your response.
So you now have backup NASes for each other.
Do you still run RAID on any one of them?
Which mode of RAID do you run & why?
I am trying to figure out if I should run my primary NAS on RAID 1 or 5 & have a backup NAS without any RAID.

 

[Bill321]

Thanks Bill for your response.
So you now have backup NASes for each other.
Do you still run RAID on any one of them?
Which mode of RAID do you run & why?
I am trying to figure out if I should run my primary NAS on RAID 1 or 5 & have a backup NAS without any RAID.

I have a Thecus N5200 (non-Pro) running three 1 tb disks in linear mode (no raid.) I run a wake on lan command and rsync command from the XP box (listed below) and shutdown the NAS automatically when rsync is finished using the shutdown module available for the N5200.

The second NAS is a home built box running Ubuntu server and Webmin in Raid 5 (four 1 TB drives.) I setup this using Raid 5 just to see how it worked (and because I had an extra drive) and have left it that way. OS is on and it boots off of a USB Key drive. I run a wake on lan command from the XP box listed below - and run rsync from the XP box to this one using a Cron job. The last line in the cron job shuts down the server when the rsync commands are finished.

The primary server (data and media, including Squeezecenter and BeyondTV) is home built, and it runs XP Pro with the data on a linear array (three 1 TB drives) using the dynamic disk mode of XP Pro. This box uses XP mainly because of BeyondTV (which my wife likes). I used Deltacopy to setup rsync to backup to the other two boxes.

I don't consider Raid to be necessary for any of these three boxes - I always have a fresh backup that is no more than 12 hours old and the two backup devices are never on for more than about 30-60 minutes a day at most. Just yesterday my wife deleted by accident a show she had not yet watched - I turned on one of the backup servers and copied it over - took no more than 5 minutes of effort. With Raid 1 as my only backup, the file would have been gone for good.

I realize that two backup servers is overkill. But, with over 1.5 tb of data and media files, I felt uncomfortable with only one backup the last time I had a major crash (using Windows Home Server - but that is another story). During the 24 hours or so it took me to restore the server, I had no backup at all for most of the files (I only keep the critical stuff like tax files and photos in the off-site backup.)

Bill

 

[wonmoi]

Thanks again Bill for sharing.
I am still a NAS newbie so I don't understand what you mean by 'run a wake'.
Can you please explain?
So your 2 backup NASes are programmed to auto shut down after each rsync, does it mean you have to power on/re-boot all 2 NASes manually before a backup?
What are the advantages of running dynamic mode on your main server?
In your opinion, do you think I should at least have the 1st primary NAS running on RAID 1 or 5 for continue online access & the other secondary NAS serving as a back up?
Can you offer any advices on suitable NASes to purchase for this set-up?

 

[claykin]

Tim

Any idea what block size Synology, Qnap and Thecus are currently using?

It sure seems that Netgear jumped prematurely to 16K blocks. 4K blocks support up to 8TB arrays and that covers even the new Readynas Pro equipped with 1.5TB drives in XRAID mode.

 

[thiggins]

Any idea what block size Synology, Qnap and Thecus are currently using?

Nope, but I can ask. But, first, let's make sure I know what you want.
I have found that people tend to use chunk/block/stripe interchangeably.

Chunk / stripe size (I know it's not the same as block) for Thecus is 64K.

 

[yoh-dah]

It sure seems that Netgear jumped prematurely to 16K blocks. 4K blocks support up to 8TB arrays and that covers even the new Readynas Pro equipped with 1.5TB drives in XRAID mode.

FYI, 16K page/block size allows for faster performance especially with our custom NSP. There's also advantage in terms of providing better prevention against fragmentation. Recovery can be performed on any Sparc or IA-64 (Itainium)-based systems as someone posted, but it can also be done by any ReadyNAS running on that processor (600, X6, 1100, NV, NV+, Duo), and if you don't want to purchase a new system, there's plenty in the field where you should be able to get a used one off Ebay. That said, NETGEAR warranties the Duo for 3 years, and 5 years for NV+, 1100, and the Pro, so if anything happens during that time, NETGEAR Support can help with recovery. Beyond that, NETGEAR offers recovery service at a *very* reasonable price.

I hope that helps, and please let me know if you have further questions.

 

[claykin]

Tim

I'm referring to the EXT3 block size. Whereas RADIATOR V3.x used 4KB blocks, RADIATOR V4.x is using 16KB and not readable by x86. What are Netgear's competitors using? I believe most, if not all, used EXT2 or 3 for their file system.

I'm a little perturbed at Netgear for choosing to exclusively use 4KB when its totally unnecessary for their current products and any arrays under 8TB. All theya re doing is making it more difficult for users to extract data from a drive removed from a Readynas product.

Nope, but I can ask. But, first, let's make sure I know what you want.
I have found that people tend to use chunk/block/stripe interchangeably.

Chunk / stripe size (I know it's not the same as block) for Thecus is 64K.

 

[claykin]

Yoh Dah

If you had 2 NV+ units configured the same, can you show a measurable performance improvement between 1) NV+ running RADIATOR V3.x with 4KB blocks and 2) another NV+ with RADIATOR V4.x with 16KB blocks?

How many end users do you know with a Sparc workstation and/or Itanium machine? I know a grand total of 0!

Is it really worth the tradeoff where you take away the end users ability to read a disk on another system?

FYI, 16K page/block size allows for faster performance especially with our custom NSP. There's also advantage in terms of providing better prevention against fragmentation. Recovery can be performed on any Sparc or IA-64 (Itainium)-based systems as someone posted, but it can also be done by any ReadyNAS running on that processor (600, X6, 1100, NV, NV+, Duo), and if you don't want to purchase a new system, there's plenty in the field where you should be able to get a used one off Ebay. That said, NETGEAR warranties the Duo for 3 years, and 5 years for NV+, 1100, and the Pro, so if anything happens during that time, NETGEAR Support can help with recovery. Beyond that, NETGEAR offers recovery service at a *very* reasonable price.

I hope that helps, and please let me know if you have further questions.

 

[yoh-dah]

If you had 2 NV+ units configured the same, can you show a measurable performance improvement between 1) NV+ running RADIATOR V3.x with 4KB blocks and 2) another NV+ with RADIATOR V4.x with 16KB blocks?

The memory management architecture in 2.6 kernel used in V4 differed enough from 2.4 in V3 such that we had to recoup by using a larger page/block size. So if we had stuck to 4K page size, performance would not have been close to where it is today.

How many end users do you know with a Sparc workstation and/or Itanium machine? I know a grand total of 0!

Well, that's the options. But if somehow your Duo would blow up and your disks were still intact, your easiest option is to get a replacement diskless Duo -OR- NV+ and you'd be good to go.

Is it really worth the tradeoff where you take away the end users ability to read a disk on another system?

Your point taken, but in the grand scheme of things, you are covered for at minimum 3 years (check warranty of other NAS) in case your ReadyNAS self-destructs. Frankly I can think of only 1 case in the last 4 years where that would have happened. The SOC, motherboard, and backplanes are pretty simple and reliable. Typical failures are confined to disk, PSU, or the fan, any of which would be end-user replaceable.

 

[claykin]

Yoh Dah

Diskless Duo? Where can I get such a beast?

 

[yoh-dah]

Diskless Duo? Where can I get such a beast?

I think it may be available in some parts of the world but not in NA, at least not yet.

 

[beisser]

yeah you can buy it in germany for example.. just google for rnd2000.

 

[wonmoi]

Yoh Dah

If you had 2 NV+ units configured the same, can you show a measurable performance improvement between 1) NV+ running RADIATOR V3.x with 4KB blocks and 2) another NV+ with RADIATOR V4.x with 16KB blocks?

How many end users do you know with a Sparc workstation and/or Itanium machine? I know a grand total of 0!

Is it really worth the tradeoff where you take away the end users ability to read a disk on another system?

Hi claykin,
given this lack of drawback of the ReadyNas Duo (ability to read data on disk with regular desktops), do you still recommend I get it over the D-Link DNS-323 which can be readily read?
I am looking at these two NAS & weighing their pros & cons.

 

[fullroast]

Hi yoh-dah - Thanks for the great input. Just a minor question - what does NSP stand for? Network Storage Processor?

 

[yoh-dah]

Hi yoh-dah - Thanks for the great input. Just a minor question - what does NSP stand for? Network Storage Processor?

Yes, specificially the IT3107 NSP used on the Duo.