D-Link 2-Bay Network Attached Storage Enclosure DNS-321
From D-Link
The D-Link 2-Bay Network Storage Enclosure (DNS-321) is the perfect way to store, share, and safeguard your documents, music, videos, and photos. With the D-Link tool-less installation, easily insert up to two SATA drives1 without any tools or attaching any cables. Additionally, the built-in UPnP AV media server enables streaming of digital content to compatible network media players (such as those found in the D-Link MediaLounge product line) as well as popular media player applications used in computers.
- Brand: D-Link
- Model: DNS-321
- Platform: Windows
- Format: CD
- Dimensions: 7.25" h x 8.25" w x 11.00" l, 5.35 pounds
- Memory: 128000MB DRAM
- Hard Disk: 1GB
- Processors: 1
- Native resolution: 640x480
- Display size: 669.2913385827
One of the better home NAS devices
I've been pleased with the reliability and performance of the DNS-321. I was hoping the Gigabit transfer speeds would be significantly faster, but it seems to top out at 14-16 MBps (MegaBytes per sec). This is on the upper end of most consumer NAS boxes, including D-Link's tried & true DNS-323.
Pros:
. Runs cool & quiet.
. Spins down the HD when idle to conserve power.
. Rock-solid operation (no reboots necessary in the month I've had it).
Cons:
. Larger drives (1TB and up) can get "stuck" at 94% during the format phase, but eventually it will complete.
. User permissions setup is clunky. This is common among consumer-level NAS boxes though.
. User access permissions are cleared on reboot :(
. No firmware update yet (v1.0). D-Link tech support says they've fixed most of the problems above and are testing the new firmware for public release. The cons are relatively minor to me, and once fixed in firmware, this will be a 5-star product.
Notes:
Opt for a low-power (and low-heat) HD to use in an external enclosure. Transfer rates on this generation of NAS will never approach the max throughput of HDs, so using a fast 7200rpm drive is a waste of money and power. Extra heat from the faster drives may cause issues down the road. Recommended low-power models are the Western Digital GreenPower and Samsung EcoGreen.
UPDATE 11/30/2008: D-Link has released firmware 1.01 which fixes the issue with access permissions being cleared on reboot. It also claims to support 1.5 TB hard drives.
http://support.dlink.com/products/view.asp?productid=DNS-321
UPDATE 5/8/2009: User account access control has an issue in all firmware versions, from the original 1.0 release to the latest beta. Basically the setting to allow All users to access a share disappears. Resetting to defaults sometimes brings it back, but shares configured to allow All users don't work properly. Weird issues with the All checkbox and shares disappearing are very frustrating. Dlink tech support has been aware of this for 4-6 months but no fix is in sight.
I now rate this at 3 stars.
5 stars for nice features, overall 0 stars for corrupting my data
Well, it was working fine for the features I was using. Immediately updated to their latest firmware release. Put 2 1TB drives in it, all the backup options (rebuild drive, etc.) seemed fine as I played around with swapping drives out. Then I tried to copy all of my current data over to this NAS box. After about a full day of copying (I have several hundred gigs of files) I went to check the status of the backup.
The backup had completed... HOWEVER, since I had turned on data validation (rereads the destination and source files and compares after the backup) it noted that out of the 1000s of files I had backed up that 12 of them were "not equivalent to the source files".
I took down the names of the files and then did a hex dump compare of the old and new files. To my surprise the files that were copied onto the NAS box had *exactly* 76 bytes of zero in very specific relative offsets in each file. It was always at hex offsets with the last 3 nibbles of the file offset being in the range of xfb4-xfff that were all zero, in all of the "corrupted" files.
Puzzled, I did some Google searching and found that there was a Linux kernel bug found at the end of 2006 that just happens to exactly match this behavior! The kernel was losing the "dirty bits" (modified memory page indicators) when it was writing to ext2 or ext3 file systems (this box uses ext2). This only happened on certain "chunks" (76 bytes for the Linux case) if they were the 76 bytes that fall at the end of a 4k memory page boundary (the last 76 bytes of a 4k page are... you guessed it!! bytes xfb4-xfff).
The data I was transferring was from a Windows XP machine and this NAS box is internally running.. yep, LINUX! I believe they likely have a version of kernel running on this thing that was silently corrupting my data, as all the issues seem to exactly match my conditions.
That is the WORST kind of data corruption ("silent") because there were NO error indications at ALL except for when it had done the final recompare, which good thing I had turned that on or I would have NEVER known my data was being corrupted as it was copied to this NAS box!
I notified the D-Link tech support people about this issue, and they responded back saying that they are looking into what is causing the problem (think I gave them a good enough head's up on this one!)
I promptly returned the box to get my money back and am now running w/ a RAID 1 configuration in my main PC instead of having an external NAS box.
Support notes - I stayed on the phone for the D-Link tech support number for a good 20+ minutes, all I got was the answering service kept repeating "due to a large volume of calls, ... " so I just hung up and emailed them instead. Took them about a week to get back to me (but they did).
Other gripes about the box - the little levers to remove the drives were REALLY hard to use, my thumb got sore after swapping the drives a couple times for doing the failed drive testing.
This review is specifically about the DNS-321 as that was the only one I tested, however the DNS-323 is VERY similar to this box (just basically added a print server), so I can't say if that one is any better or does the same corruption as this one does (it's quite possible).
Great NAS for the Price
If you are looking to add storage without the hassle of internal drives then this is a great device.
The setup is easy and there are plenty of configuration options via an easy web GUI. It uses the EXT2/linux file system so fragmentation is not a problem.
I have two 1 TB drives set in a raid 0 for testing purposes and this thing screams on a gigabit network.
It is a very small and quiet and looks sleek.
Overall this is the best home/small business diskless NAS system out there.
