Help optimize the performance of NAS 314

You could also try turning off AntiVirus protection.

Yes it is turn off. I logged into the NAS and try to find where I can turn off Snapshot service but I am not seeing where to turn it off.

checkmate9 wrote:
Yes it is turn off. I logged into the NAS and try to find where I can turn off Snapshot service but I am not seeing where to turn it off.

This is a setting for each share. Click on the share, then select settings. Unchecking "continuous Protection" will turn snapshots off.

Snapshots have a bigger impact on disk usage they have read/write performance. Though if your users are updating files frequently (for instance, if there is a database in the share), then there can be a significant performance impact.

There are indeed some things to speed up a NAS at a software level (defrag, fylesystem repair, freeing some space on the disks, disabling unneeded services...) but performance problems are usually bottlenecks. Why to you want to optimise the performance in the first place ? If you already have decent speeds there is not much you can do.
- Most people experience bottlenecks on their network, a single gigabit link is limited to 120Mbytes/s no matter what you do, and this number assumes a perfect network which is never the case, so expect less.
- The second bottleneck is usually CPU or hard drives. if you have SSH enabled you can check this with the "top" command, if you have idle at 0%, look at which category is used. if that's "us" or "sys" then you CPU is used by applications, if that's "wa" and you already ruled out network, then it is probably the disks.
- Then there is the RAM, usually it is not a problem on NAS. If you have SSH the "free -h" command will give you the information you need. As long as you don't use swap, you won't need to upgrade, no matter what the free category says.

If you already ruled out all that then, check the smart status of your drives, they may have some errors on them.

I suggest that you begin by benchmarking the actual system performance using NAStester, so you can get some repeatable measurements that can be duplicated by other forum members. The download is here: http://www.808.dk/?code-csharp-nas-performance

That will require a windows machine.

I agree that you should check the SMART stats for all drives, as disk errors will certainly stall the NAS when they occur. If you don't have email alerts configured, you ought to set that up.

I'd also emphasize xeltros's point on the network. If some of your users are running fast ethernet or wifi, then their performance will certainly be limited by the network. On Gigabit, write performance is degraded if the client machines have the wrong MTU (for instance if they have jumbo frames enabled, but the network doesn't support it). The jumbo frame setting on the NAS is only part of that puzzle. Those settings appear in clients (and in many cases switches).

Packet loss within the network will also kill user performance, and might not be as noticeable for other applications (for instance web browser use). A mismatched full duplex/half duplex negotiation is one potential cause (though not as common as it used to be). Often that results in a 1-2% persistent packet loss. Bad cables, or inadequate shielding in cables running through plenums can also create packet loss issues. Unfortunately the OS6 gui doesn't give you much information about packet loss. You could use SSH to get more data on physical layer issues (carrier issues, drops, overruns, etc).

Also, you can increase multiuser throughput if you use link aggregation ( for instance LACP) on the NAS. That requires support on your switch. If you are running multiple switches, you might also need to add LAG on the connections between them.

BTW, in my experience it is pretty rare for hard drive performance to be the bottleneck - at least for large file transfers. Large numbers of small files, or database I/O could be limited by hard drive latencies though. Since the RN314 supports SSD, you could potentially rebuild the NAS using flexraid, with an SSD volume and a normal RAID volume for traditional drives. Then put databases, etc on the smaller SSD volume. That would be quite a bit of work, but it is an option. One downside is that the ReadyNAS hardware compatibility list for SSDs is weak.

I forgot another bottleneck, the client computer. Most of the laptops still have 5400RPM 2.5" HDD unless you get high end machines. Given a speed of 600Mbytes/s (I assume 4 high end disks, otherwise 400-450 will be closer to reality) on the NAS, the only machine I know could follow the pace are Macs because of their PCI-Express SSD, and even there they should use thunderbolt for network connection or a 10Gbit/s ethernet adapter. Of course custom machines with PCI-Express SSD will do the trick too or anything with at least 2 SSD in raid0.

I agree that disks are not usually a limiting factor for low end NAS, however when you begin to go with xeon CPU chances are they are. An hexacore@2Ghz will likely not be the bottleneck and they usually come bundled with 16Gb Ram and an incredible number of network cards. In this high end configuration network is still the main bottleneck but HDD are second. However I agree that the 314 is far away from having such an horsepower and is likely to not see any difference here.
I don't believe SSD will make any difference for anything less than 5xx or even 7xx series here unless you are working with a tremendous amount of small files (size in bytes or kbytes) or maybe using iSCSI for VM.

With a 7200 RPM hard drive, sequential disk I/O will be faster than a gigabit network can carry. But if you are not doing sequential reads/writes, then you can end up with about ~80 IOPS per second and ~350 KB/sec throughput. http://storageioblog.com/part-ii-iops-hdd-hhdd-ssd/

So if even one user is running a database application (where the I/O is not sequential), he can greatly reduce the NAS performance. Using an SSD for the databases completely fixes that.