We put the Synology DS2015xs through some IOMeter tests with a CIFS share being accessed from up to 25 VMs simultaneously. The following four graphs show the total available bandwidth and the average response time while being subject to different types of workloads through IOMeter. The tool also reports various other metrics of interest such as maximum response time, read and write IOPS, separate read and write bandwidth figures etc. Detailed listings of the IOMeter benchmark numbers (including IOPS and maximum response times) for each configuration are linked below:
We see that the sequential accesses get saturated around 700 MBps, similar to what we found in our evaluation of the unit as a DAS. In the Random 8K 70% Reads case, we see a sudden drop after more than five clients come into the mix - we believe it has to do with the smbd processes saturating the CPU cores completely. On the positive side, we find that the bandwidth numbers and response times are excellent across the board, better than all the other NAS units that we are comparing against.
Actually RAID 10 is used far more than RAID 5 or 6. With RAID 5 actually not even being listed as an option with Dell anymore. The random write IOPS loss from RAID6 is not worth it vs RAID10. Rebuild times are 300% faster with RAID10.
The marginal cost of adding another pair of drives to increase the RAID10 array would be easier than trying to increase IO performance later on a RAID6 array.
But then again, this is mostly for combining os, apps, and storage (VM). For just storage, it may not make any difference depending on the how many users or application type.
That's missing the point entirely. If you lose a drive from each subset of RAID10, you're done. It's basically a RAID 0 array, mirrored to another one (RAID 1). You could lose one entire array and be fine, but lose one disk out of the working array and you're finished. The point of RAID 6 is you can lose any 2 disks and still operate. So most likely scenario is you lose one, replace it and the rebuild is going and another fails.
RAID0 is pure performance, RAID1 is drive for drive mirroring, RAID10 is a combination of the two, RAID 5 offers one drive (any) redundancy. Not as useful anymore. RAID 6 offers two. The other factor is you lose less storage room with RAID 6 then RAID 0. More drive security, less storage loss. More overhead sure but that's still nothing for the small business or home user's media storage. So, assuming 4TB drives x 8 drives... RAID 6 = 24TB or usable storage space (well, more like 22 but we're doing simple math here). RAID 10 = 16TB. And I'm all about huge storage with as much security as reasonably possible.
And who gives a crap what Dell thinks anyhow? We never had more trouble with our hardware then the few years the company switched to them. Then promptly switched away a few years after.
RAID 10 is not exactly 1+0, at least not in the Linux kernel implementation. In any case, RAID 10 can have more than 2 copies of every chunk, depending on the number of available drives. It is a tradeoff between redundancy and disk usage. With 2 copies, every chunk is safe from a single disk failure and the array size is half of the total drive capacity. With 3, every chunk is safe from two-disk failure, but the array size is down to 1/3 of the total capacity. It is not correct to state that RAID 10 cannot withstand two-drive failures. Also, since not all chunks are on all disks, it is also possible that a RAID 10 survives a multi-disk failure. It is just not guaranteed that it will unless copies > 2. A positive for RAID 10 is that a degraded RAID 10 generally has no corresponding performance degradation.
There's the FreeNAS Mini that can be ordered via Amazon. I think you can order it sans drives or pre-populated with four drives. I've been considering getting one, but I don't know how well they perform vs a Syn or other COTS NAS boxen.
iXsystems sells a few different lines of ZFS capable hardware. The FreeNAS Mini which was mentioned wouldn't compete with this unit as it is more geared towards the home user. I see this product as more SOHO oriented than consumer level kit. The TrueNAS products sold by iXsystems are much more expensive than the consumer level gear, but you get what you pay for (backed by expert FreeBSD developers, FreeNAS developers, quality support.)
Infortrend has a line of NAS that use ZFS. The EonNAS Pro 850 most closely lines up with the NAS under review in this article. Infortrend's NAS boxes seem to have some pretty advanced features. I would love to have Anandtech review them.
I'd be more interested in seeing a review of the 210/510 because they more closely approximate mainstream SOHO NASes in specifications; although at $500/$700 they're still a major step up in price over midrange QNap/Synology units.
It's not immediately clear from their documentation, I'm also curious if they're running a stock version of OpenSolaris that allows easy patching from Oracle's repositories, or have customized it enough to make customers dependent on them for major OS updates.
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Dug - Saturday, February 28, 2015 - link
Actually RAID 10 is used far more than RAID 5 or 6. With RAID 5 actually not even being listed as an option with Dell anymore.The random write IOPS loss from RAID6 is not worth it vs RAID10.
Rebuild times are 300% faster with RAID10.
The marginal cost of adding another pair of drives to increase the RAID10 array would be easier than trying to increase IO performance later on a RAID6 array.
But then again, this is mostly for combining os, apps, and storage (VM). For just storage, it may not make any difference depending on the how many users or application type.
SirGCal - Sunday, March 1, 2015 - link
That's missing the point entirely. If you lose a drive from each subset of RAID10, you're done. It's basically a RAID 0 array, mirrored to another one (RAID 1). You could lose one entire array and be fine, but lose one disk out of the working array and you're finished. The point of RAID 6 is you can lose any 2 disks and still operate. So most likely scenario is you lose one, replace it and the rebuild is going and another fails.RAID0 is pure performance, RAID1 is drive for drive mirroring, RAID10 is a combination of the two, RAID 5 offers one drive (any) redundancy. Not as useful anymore. RAID 6 offers two. The other factor is you lose less storage room with RAID 6 then RAID 0. More drive security, less storage loss. More overhead sure but that's still nothing for the small business or home user's media storage. So, assuming 4TB drives x 8 drives... RAID 6 = 24TB or usable storage space (well, more like 22 but we're doing simple math here). RAID 10 = 16TB. And I'm all about huge storage with as much security as reasonably possible.
And who gives a crap what Dell thinks anyhow? We never had more trouble with our hardware then the few years the company switched to them. Then promptly switched away a few years after.
DigitalFreak - Monday, March 2, 2015 - link
You are confusing RAID 0+1 with RAID 10 (or 1+0). http://www.thegeekstuff.com/2011/10/raid10-vs-raid...0+1 = Striped then mirrored
1+0 = Mirrored then striped
Jaybus - Monday, March 2, 2015 - link
RAID 10 is not exactly 1+0, at least not in the Linux kernel implementation. In any case, RAID 10 can have more than 2 copies of every chunk, depending on the number of available drives. It is a tradeoff between redundancy and disk usage. With 2 copies, every chunk is safe from a single disk failure and the array size is half of the total drive capacity. With 3, every chunk is safe from two-disk failure, but the array size is down to 1/3 of the total capacity. It is not correct to state that RAID 10 cannot withstand two-drive failures. Also, since not all chunks are on all disks, it is also possible that a RAID 10 survives a multi-disk failure. It is just not guaranteed that it will unless copies > 2. A positive for RAID 10 is that a degraded RAID 10 generally has no corresponding performance degradation.questionlp - Friday, February 27, 2015 - link
There's the FreeNAS Mini that can be ordered via Amazon. I think you can order it sans drives or pre-populated with four drives. I've been considering getting one, but I don't know how well they perform vs a Syn or other COTS NAS boxen.usernametaken76 - Friday, February 27, 2015 - link
iXsystems sells a few different lines of ZFS capable hardware. The FreeNAS Mini which was mentioned wouldn't compete with this unit as it is more geared towards the home user. I see this product as more SOHO oriented than consumer level kit. The TrueNAS products sold by iXsystems are much more expensive than the consumer level gear, but you get what you pay for (backed by expert FreeBSD developers, FreeNAS developers, quality support.)zata404 - Sunday, March 1, 2015 - link
The short answer is no.bleppard - Monday, March 2, 2015 - link
Infortrend has a line of NAS that use ZFS. The EonNAS Pro 850 most closely lines up with the NAS under review in this article. Infortrend's NAS boxes seem to have some pretty advanced features. I would love to have Anandtech review them.DanNeely - Monday, March 2, 2015 - link
I'd be more interested in seeing a review of the 210/510 because they more closely approximate mainstream SOHO NASes in specifications; although at $500/$700 they're still a major step up in price over midrange QNap/Synology units.It's not immediately clear from their documentation, I'm also curious if they're running a stock version of OpenSolaris that allows easy patching from Oracle's repositories, or have customized it enough to make customers dependent on them for major OS updates.
DanNeely - Monday, March 2, 2015 - link
Also of interest in those models would be performance scaling to more modest hardware, the x10 units only have baytrail based processors.