Western Digital My Cloud DL4100 Business NAS Review
by Ganesh T S on March 4, 2015 5:30 AM EST- Posted in
- NAS
- Storage
- Western Digital
- Enterprise
Multi-Client iSCSI Evaluation
As virtualization becomes more and more popular even in home / power user settings, the importance of the iSCSI feature set of any COTS NAS can't be overstated. Starting with our ioSafe 1513+ review, we have started devoting a separate section (in the reviews of NAS units targeting SMBs and SMEs) to the evaluation of iSCSI performance. NAS vendors have multiple options when it comes to implementing iSCSI LUNs. By far, the most common and simplest method is in the form of regular files. Western Digital adopts that method too. WD also allows multiple initiators to connect to a single iSCSI target.
We evaluated the performance of the WD My Cloud DL4100 with file-based LUNs. In the first case, we configured a single LUN and had multiple initiators from different machines connect to it. In the second case, we created one LUN/target for each initiator to connect to. The standard IOMeter benchmarks that we used for multi-client CIFS evaluation were utilized for iSCSI evaluation also. The main difference to note is that the CIFS evaluation was performed on a mounted network share, while the iSCSI evaluation was done on a 'clean physical disk' (from the viewpoint of the virtual machine).
Performance Numbers
The four IOMeter traces were run on the physical disk manifested by mapping the iSCSI target on each VM. The benchmarking started with one VM accessing the NAS. The number of VMs simultaneously playing out the trace was incremented one by one till we had all 25 VMs in the fray. Detailed listings of the IOMeter benchmark numbers (including IOPS and maximum response times) for each configuration are linked below:
- WD My Cloud DL4100 - 4 HDDs / RAID-5 / 2x 1G - Single LUN (Regular File)
- WD My Cloud DL4100 - 4 HDDs / RAID-5 / 2x 1G - LUNs (Regular Files)
The performance issues we encountered in the single-client iSCSI benchmarks are evident here also. The other 4-bay NAS units we have put through these tests (the Seagate NAS Pro 4-bay as well as the Synology DS415+) exhibit better numbers as well as consistency compared to the WD My Cloud DL4100.
Towards the end of the iSCSI testing process, we ran a script on the clients' side to disconnect the iSCSI targets one by one, while refreshing the My Cloud DL4100's web UI's iSCSI page at the same time. During this process, the unit froze up completely - the web UI wasn't reachable, the LCD navigation froze and a SSH connection was refused - there was no way out but to yank out the power and restart the unit. Unfortunately, the logs reported only a power failure and this was not a repeatable issue. In addition to general performance improvements, it appears that the My Cloud OS could do with stability QA also.
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kepstin - Wednesday, March 4, 2015 - link
Hmm, you say "the board must definitely be sporting a PCIe - USB 3.0 bridge", but then don't bother to look up the PCI ids from the lspci output. The device "1b21" "1142" is an ASMedia ASM1042A USB 3.0 Host Controller.pwr4wrd - Wednesday, March 4, 2015 - link
Building a custom FreeNas or Nas4Free box depending on your needs is a much better solution than any one of these anemic underpowered and overpriced solutions. Presence of ZFS on FreeNas is by far the most critically important aspect. If data loss prevention and integrity top priority, which should be, there are two great articles by Robin Harris. These articles are titled "Has Raid5 Stopped working?" and "Why Raid5 stops working in 2009" can be found with a quick search. Mr. Harris clearly explains the inadequacy of Raid5 and 6 as viable storage solutions. As far as I am concerned, most of these off the shelf units are not good options for data safety. Considering the rock solid encryption option ZFS offers its value becomes even more important.Black Obsidian - Wednesday, March 4, 2015 - link
People considering COTS NAS boxes are doing so either because they're a business that needs real support, or a consumer who needs ease-of-use and hand-holding, all of which being areas that a custom FreeNAS/Nas4Free box utterly fails to deliver. While both are great products, their target market doesn't have much overlap with the target market of these COTS boxes.The articles by Robin Harris are unimpressive. He assumes that the advertised BER is a maximum, where in fact it appears to be a minimum (and several consumer lines advertise higher than 10^14 anyway). He also over-dramatizes an array rebuild failure due to read error; in that event, you simply create a new array from scratch and restore data from backups, since unlike Harris, you remember that RAID is a solution for AVAILABILITY, not backup.
pwr4wrd - Wednesday, March 4, 2015 - link
I see your points. Our data is very important to us at our business. So we have to approach things as worst case scenario possibility. And some arguments made here make no sense. For businesses that NEED serious support this is NOT that SERIOUS of a product. And yes FreeNas does offer home/soho version of the product that was very well reviewed. For the individual that needs "hand-holding" availability of RAID means next to nothing. A simple back up drive from costco would do fine.Spoogie - Wednesday, March 4, 2015 - link
This has been debunked, which is why ZFS adoption has not taken hold.http://www.high-rely.com/blog/why-raid-5-stops-wor...
pbrutsche - Wednesday, March 4, 2015 - link
Sorry, that link doesn't explain why ZFS hasn't taken hold.Spoogie - Wednesday, March 4, 2015 - link
The fact that IT pros haven't adopted it in in spite of this sort of debunked fear mongering makes it pretty clear. Don't believe it? Fine, then use ZFS if it makes you feel better.pwr4wrd - Wednesday, March 4, 2015 - link
How can you fear monger in order to capitalize on a free product?dave_the_nerd - Wednesday, March 4, 2015 - link
It's not free if you have to buy a support contract and consulting services from iXSystems.dave_the_nerd - Wednesday, March 4, 2015 - link
Are you running your business without support agreements/maintenance contracts on your servers? *horror*