HP EX487 MediaSmart Server

[thecave]

This article mentions the option of backing up the server to Amazon's S3, but doesn't discuss options for backing up to an external drive or a networked drive. I know that WHS now supports backing up the server, but am having trouble finding out how this is accomplished.

I assume that the server includes software that will automatically back up to an external disk. Can anyone comment on what the sofware is and how well it works?

[corndog]

According to the article, the HP will back up to a USB disk but only when you ask it - not automated. And it will also NOT back up to a local network location.

I have a solution for mine. I have an old ReadyNAS 1100 from yesteryear still running on my LAN. I call it "Old Faithful". It's very very slow compared to all this new stuff but Netgear built a LOT of backup options into it.

What I do is this - create a "backup user" on the MSS - mine is called "bkup". Give this user read-only access to all shares. Then configure a backup job on the ReadyNAS for each share on the MSS. Set the ReadyNAS to "pull" from the MSS using Windows/NAS (Timestamp) setting. Schedule the job, and I'm all set. Once a day, the ReadyNAS connects to the MSS and copies only the files that have changed. It's an rsync-like kludge but it works wonders.

ReadyNAS doesn't get enough props for their myriad backup methods. QNAP and Thecus don't even come close, and let's not even get started on WHS. I'm basically covering up for WHS' backup inadequacy with my ReadyNAS.

[beq]

After reading the SmallNetBuilder review, I wonder how WHS can offer such great cached write (and to some extent read) performance for smaller mainstream file sizes -- compared to Linux NASes? And how pronounced this effect is in day-to-day usage in the real world? On the other hand, I don't like the steep fall-off in read (and to some extent write) performance past the 1-2GB file size. I'm also not sure how I feel about relying on the OS-level "Folder Duplication" functionality of WHS vs low-level RAID redundancy. Personally I would always want to make all of my data redundant anyways...

I do like the Amazon S3 cloud storage support via add-in though, and I wish other NASes have this. I read that the ReadyNAS NVX is coming with a ReadyNAS Vault online storage subscription, but the description makes it sound like a local program that you install on a client PC instead of native support on the NAS. I remember that Jungle Disk had announced plans to make a version for the various Linux NASes (they already have a version for WHS), hopefully sooner rather than later. Perhaps in the NAS market Jungle Disk could become the solution for Amazon S3/Rackspace Mosso Cloud Files what TwonkyMedia is for multimedia streaming...

In any case, I agree that the HP EX487 is impressively cheap at under $600 on the street with 1.5TB disk space.

[corndog]

Beq,

I share that question also. According to the charts, the new HP WHS is hitting 340MB/sec average write, which is basically about 3 times the maximum throughput of gigabit ethernet! There is no way that this can be simply attributed to the NAS's cache, because it still has to get FROM the test machine TO the NAS through a 1gigabit network connection, before it can even load into the cache. So there's something else going on. I've read that WHS and Vista both use an enhanced "version 2" flavour of the CIFS filesystem that is not yet built into the versions of samba that are used on Linux-based NASes.

So if we assume it is this newer cifs version that is providing the jump in performance, we still have to figure out why the throughput is nearly 3 times the absolute limit of the network media.

The first thing that comes to mind is compression. I remember the old bonnie++ filesystem benchmark on Linux taking a MAJOR beating from critics because all of the test files were filled with reams and reams of zeroes. Of course, any smart network file protocol that used compression would artificially inflate its benchmark because it could massively compress those zeroes for transport across the network.

If Tim's iozone tests use all zeroes in their test files (Tim, can you comment on this at all?) then I think we might be onto a compression artefact that is unfavourably biasing the tests toward WHS. But from my perspective this is just conjecture at the moment.

Comments all?

[thiggins]

Caching can happen on both ends of the connection. When you see performance above what the network connection supports, that is from OS cache on the iozone machine.

The answer could lie in the fact that there are Windows OSes involved on both ends of the connection. But iozone does not use any of the Windows enhanced-performance system calls. I suspect it is more the use of larger transfer sizes as discussed in How To Build a Really Fast NAS - Part 6: The Vista (SP1) Difference. This could be easily confirmed with a Process Monitor trace.

I checked an iozone .tmp file. It is not all, but it is mostly zeros.

This is one reason why I'm glad that I added file copy tests. If you look at those results, you might ask what tricks the ReadyNAS Pro is using to goose to up near 100 MB/s!

[corndog]

Hi Tim,

That's very interesting, and it raises even more questions. From that it would be a reasonable deduction that Microsoft has somehow configured Vista SP1 to very aggressively cache on the client side, ONLY when contacting a Windows Server. The other way of saying this is that Microsoft has intentionally hobbled performance when contacting a non-Windows Server. That raises the stench of nastiness from Microsoft which really wouldn't surprise me...

If we can rule out compression by insisting the test files must contain strings of random numbers, and use test files that are so collossally massive that all caches on client and server are completely overwhelmed, the best we should ever be able to hit is 125MB/sec, correct?

And that's assuming our network protocol is almost 100% efficient - no loss for acknowledgements and error correction. So most likely it might be more realistic to expect 110MB/sec or something like that due to necessary protocol inefficiency.

And then because ethernet is a Collision-based architecture, even with the increase in collision-avoidance provided by switching, it might be reasonable to expect to do no better than 100MB/sec.

... which would mean the Netgear Pro is unbeatable unless we go to 10Gig ethernet?

I'm probably missing something....

[thiggins]

Don't get too far into M$ conspiracy theories there, corndog! We already know that there are Microsoft system calls that can be used to enhance file copy performance. If that is what's in play, then it's just an advantage to be gained from using an all Microsoft solution vs. "intentionally" crippling performance when not using an MS to MS transfer.

Non-cached performance is going to be limited by the max speed of the network connection. Taking overhead into account, I'm using a rule of thumb of 100 MB/s as the max for a gigabit Ethernet connection.

As for the ReadyNAS Pro being unbeatable.... remember that it also gets its high average number in the charts partly from cached performance. So if it can do it, so can others.

[corndog]

Point taken

It's also quite convenient to expect 100MB/sec because it's basically taking your bit rate and dividing by 10 for byte rate, which is nice and easy.

I'm waiting with baited breath for the samba team to incorporate the cifs v2 changes in samba. Nicely, the EU convinced Microsoft to release the specs for this protocol to the community, so the samba team can be on a better footing with this new version than they are on their existing platform which is based on reverse engineering.

When it comes out in a stable version of Samba, it will be very interesting to see the effect on our Small Business NAS industry. If the performance of WHS is any indication, we might see a very large performance jump from the first vendors that embrace the new samba version.

Whoohoo!

[ymboc]

Originally Posted by thiggins

This is one reason why I'm glad that I added file copy tests. If you look at those results, you might ask what tricks the ReadyNAS Pro is using to goose to up near 100 MB/s!

Have you considered using iozone's '-c' switch to help reduce the effect of client-side caching on the write performance results?

I do realize it was intended for use with NFSv3 but it does appear to be working as intended on the win32 platform.

If you've fiddled with this already can you comment on how well (or poorly) iozone '-c' read & write performance results compare with your file copy results?

The EX487's write performance scores sure are impressive but when they're more than twice as high as what the transmission media can theoretically support, do the results still reflect reality?

[thiggins]

Our iozone testing has always included cache effects for both the NAS and client OS. See Why Cache Matters in NAS Performance.

We added the Vista SP1 file copy benchmarks to provide more "real world" performance information.