NAS with SSD

[mperrigon]

I am looking at building a NAS unit using SSD drives and I am getting stuck on the numbers.

According to Samsung the 840 Pro SSD drive operates at 540 MB/s sequential read and 520 MB/s sequential write.

Looking at NAS units the sinology DS412+ says it's compatible with that drive but it also says 205.68 MB/sec Reading, 182.66 MB/sec Writing.

Thinking that means the unit won't keep up with the drives I started looking around and found the QNAP TS-469U-RP 4-Bay NAS and it also says "Exceptional Performance: 221.8 MB/sec Reading, 220.8 MB/sec Writing"

Does that really mean that a $1200 NAS unit can't keep up with a $400 SSD drive?

 

[VirtualLarry]

Does that really mean that a $1200 NAS unit can't keep up with a $400 SSD drive?

More than likely - yes.

 

[mperrigon]

any recommendations on an affordable NAS that can keep up?

 

[dighn]

most NAS in this category are using gigabit ethernet, which has a maximum transfer rate of 125 MB (theoretical) anyway. if you look at the specs the quoted speed is using link aggregation with its two gige ports.

if you want higher speeds you'll need to go link aggregation with even more ports, or go to another phy layer like 10 gige or fibre. is that really what you are looking for?

 

[BonzaiDuck]

most NAS in this category are using gigabit ethernet, which has a maximum transfer rate of 125 MB (theoretical) anyway. if you look at the specs the quoted speed is using link aggregation with its two gige ports.

if you want higher speeds you'll need to go link aggregation with even more ports, or go to another phy layer like 10 gige or fibre. is that really what you are looking for?

I'm just guessing he needs to think about it some more.

I use SSDs for my server's boot -system disk, the daily incremental backup of that disk, and yet another for the paging/swap-file for the entire server and the volume shadow copies. These SSDs are 60GB in size -- each one. Everything else is NAS hard disks -- right now, three 2TB drives. A fourth is awaiting installation after I tie up some loose ends. The drive-pool itself would then be 8GB, with about 180GB of total SSD storage for the OS, its backup, the swap-file and volume shadow copies.

The NAS hard disks are deployed in a drive-pool, and the speed of access for duplicated files looks like it reaches 300 MB/s read rate. This might still be limited by gigabit Ethernet full-duplex -- I hadn't really thought about it. [Off the top of my head, it seems as though full-duplex G-bit is still a tad slower than what the HDD controllers show as throughput.] But it's fast enough for a server with four client machines.

I just don't think it makes sense to invest that much in SSDs for server disks -- even for a multitude of users. It's more practical to use an SSD for the server-OS boot-drive; access to the server from the console, through Remote Desktop Connection or the server's Dashboard interface is fast and doesn't hesitate. but for user files -- even (and most certainly) video files, DVR captures -- it's faster than it needs to be.

Maybe the OP has some more specialized intention for his NAS or server. I couldn't say -- only the OP can explain.

Even for me, the use of the smaller SSDs is overkill, and I do think they're network-limited. But the equal reason I chose to use them was the reduced power draw. If the OS only takes up about 20+ GB, choices of hard drives would mean larger disks, and no matter how large or small, power draw would be equivalent for HDDs.

 

[bunnyfubbles]

any recommendations on an affordable NAS that can keep up?

affordable is pretty much impossible at this point

consumer networks are pretty much limited to gigabit LAN speeds

Gigabit Ethernet (GbE) = 1gbps/1000mbps (125MB/s)

eSATAII = 3gbps

USB3.0 = 5gbps

eSATAIII = 6gbps

Thunderbolt and 10GbE = 10gbps

10GbE isn't really an option as its still astronomically expensive

the Sinology unit you linked to achieves faster network speeds through aggregate GbE, while this can effectively double the speed, its also a lot more complicated to set up, and not particularly practical for consumers

 

[Ayah]

the main problem for your performance/$ is the purchase of a prebuilt consumer NAS. the cost of the hardware is low, what you're paying for is dumbing down (aka ease of use), compatibility testing, design, support, etc.


1200$ can easily keep up with SSDs if you custom build and network using used infiniband gear. if you chose the defacto cheapass standard 1020 cna, it will let you do "high speed" (only 20G, but relative to typical gigabit, fast) point to point for cheap. you could do a IB network using old cheap switches like the topspin 120, but the costs can add up quickly per node.

 

[npaladin-2000]

Most NAS units don't use SSDs for this very reason. By it's definition a NAS is limited by network speeds and no gigabit Ethernet out there is going to be able to transfer as fast as an SSD. Heck, 7200 RPM drives are almost a waste in that application, that's why Western Digital's NAS-specialized drives (the RED series) are 5400 RPM.

SSDs are great for a SAN connected via 8-gig fiber or 10-gig iSCSI. Or for direct connections via SATA or SAS. But never in a NAS, waste of money.

 

[Lonyo]

Unless you wanted random read/write performance where you still aren't bottlenecked on an inexpensive SSD, but would be massively faster than a mechanical disk.

All depends on what data you're using/how you're using it.

 

[bunnyfubbles]

Unless you wanted random read/write performance where you still aren't bottlenecked on an inexpensive SSD, but would be massively faster than a mechanical disk.

All depends on what data you're using/how you're using it.

yeah, the reason you gave plus maybe a desire for silence and/or robustness (say you want to tote your NAS around and don't want to worry about fragility)

but none of these reasons really make sense for traditional NAS usage, particularly for consumers

don't really need SSD performance characteristics for handling media files or doing backups

 

[BrightCandle]

You really loose a lot of the benefits of an SSD when its in a NAS. You can't use the sustained transfer speeds because its limited by the network itself (anything above 1gbit/s is prohibitively expensive) and the random access is completely ruined by the milliseconds of round trip time due to the latency of the network, which means it doesn't really perform very well there either especially when the drive is mounted using Windows file sharing.

So in the end SSDs are either designed for very large numbers of parallel reads and writes to the same disks like you might find in an enterprise scenario with a shared folder across the company. There performance is more important than absolute size, but you will find most enterprises still typically use HDD's because they are larger and when using a number of them they can cope with many users quite well.

SSDs benefits only really come into play in local machines, accessed across the network they are almost indistinguishable from hard drives except in very particular circumstances and I suspect most home NAS's are used for big files and hence a HDD will do the job.

 

[BonzaiDuck]

You really loose a lot of the benefits of an SSD when its in a NAS. You can't use the sustained transfer speeds because its limited by the network itself (anything above 1gbit/s is prohibitively expensive) and the random access is completely ruined by the milliseconds of round trip time due to the latency of the network, which means it doesn't really perform very well there either especially when the drive is mounted using Windows file sharing.

So in the end SSDs are either designed for very large numbers of parallel reads and writes to the same disks like you might find in an enterprise scenario with a shared folder across the company. There performance is more important than absolute size, but you will find most enterprises still typically use HDD's because they are larger and when using a number of them they can cope with many users quite well.

SSDs benefits only really come into play in local machines, accessed across the network they are almost indistinguishable from hard drives except in very particular circumstances and I suspect most home NAS's are used for big files and hence a HDD will do the job.

I have to agree with all of that. But I'm using small SSDs for my WHS server -- to reduce the power consumption, and for the OS and its backup primarily. They're connected to the fastest controllers in the system -- SATA-III-capable, but using PCI-E 1.x slots. The highest read-rate monitored by StableBit Scanner is between 300 and 350 MB/s. If I get any advantage at all for the speed, it is when accessing the OS drive from the console -- not over the network.