For what feels like a couple of months now, I've decided I wanted to take a handful of external hard disks and get them on the network so they wouldn't have to move around as much.  These disks range in size from 20GB to 250GB and there are 5 of them (the 20GB only really counts because it's a physically tiny one -- and it might not even go on). 

The easiest and most obvious way is to stick a PC on and chain them all to USB (2, of course) and go.  However, this has the disadvantage of power use, cost, size, and noise.  I didn't want to do this because we've switched to laptops and I've been wanting to dump the last of our desktops; they're outdated anyway.

So, I went on a hunt for various solutions.  Most of the solutions involve no-name NAS cases that have 100Mbps ports and can hold one drive.  A nice choice, but not workable due to only have a 100Mbps port, was the Linksys NSLU2.  It has a couple of USB 2 ports for putting a couple of drives on the network. 

Another promising option was Kuro Box (by Revogear, a brand of Buffalo) (or the hardware equivalent, the Gigabit Linkstation).  This box takes a hard drive, has a couple of USB 2 ports, has gigabit ethernet, runs Linux, and is designed to be modified right out of the box. 

Now, some big issues started coming up with performance.  I tested one of the drives locally on USB 2.0 and it came in at least at 20MBps and sometimes as high as 25-28MBps (these were, for the most part, all 7200 RPM IDE disks).  I started to look around at the performance of the various NAS solutions.  I wasn't impressed at all.

The NSLU2 is on 100Mbps, right?  Well, at 100Mbps a site reported seeing up to 6MBps on FTP and only up to 3.5MBps via Samba.  Considering the link is 100Mbps, this is too bad.  100Mbps should top out at around 10MBps given protocol overheads and stuff.  Interestingly, the raw disk speeds were coming in at under 9 MBps, which is far lower than the drive the site was using should have performed.  Why?

There were no reviews of the performance of the Kuro Box HG that I could see.  However, at Tom's Networking I saw some graph's showing the normal Kuro Box outperforming both the Synology DS101 and the NSLU2, but it was pulling in less the 6MBps!

Looking at the Terastation at Tom's Networking showed it peaking at nearly 9 MBps with gigabit networking.  Given the Kuro Box is basically a drive-less Linkstation and they are all made by Buffalo this, unfortunately, seemed indicative of the sort of performance that might be seen by the Kuro Box HG.  It did see a 20-30% improvement using Jumbo packets.  However, considering that it isn't using USB 2 internally, that it can get top performance with using various RAID modes (although actually the non-RAID mode was the slowest), and that gigabit ethernet is actually faster than the 480Mbps of USB 2, you would think that it could do better. 

Tom's Networking also did a series on converting an old Xbox into a NAS.  (It's a great read, BTW.)  This sounded interesting since we'll eventually get an Xbox 360 and just have the Xbox sitting around (so to speak).  The last article in the series has some very interesting performance numbers, though.  They compare the Xbox NAS performance to direct PC to PC performance.  Here we see the Xbox peaking at just over 10MBps, a very nice number for 100Mbps networking.  The PC, however, peaked at nearly 11MBps but actually was slower in many of the tests.

This appeared to tell me that there were, perhaps, some PC problems with the performance. 

In any case, when I got around to start dumping the old desktops I ended up just installing Linux Fedora Core 4 on an old Athlon XP 1600+ system with a measly 512MB of RAM.  Inconveniently, one of our external cases died so one of those drives went into the desktop, which already had an 80GB and a 160GB disk.  Unfortunately, except for the two in the Linux system, all of the disks from the cases are formatted as NTFS.  Although there are good drivers for reading NTFS on Linux, the only drivers for writing are incomplete and run in user mode so they are slow.  (By incomplete, they mean they don't support every possible method for adding nodes to the tree that is NTFS.  This means occasionally a delete or a write will fail.  Reads never fail and data is never corrupt.)  This, however, is better than stories of having to completely reformat drives to use them with various of the above solutions.  (Ultimately, though, I'll probably reformat them with something more interesting or maybe even find a hardware RAID card for cheap.)  I haven't bothered to test the performance yet since the system only has a 100Mbps ethernet card in it right now.

While writing this, I went to check out more performance stuff at Tom's Networking (which seems to have the most frequent reviews of this stuff with easy to read data).  The ReadyNAS is a competitor to the Terastation, although usually more expensive.  Recently they release a newer X6 version.  This increases performance even more.  In fact, this system apparently however, around 20MBps when using Jumbo frames with gigabit ethernet.  With normal gigabit ethernet it looks like it can still pull in numbers above 15 MBps.  This is over 2x the performance of the Terastation and much higher performance than the other NAS devices I've mentioned.  However, it's not as flexible (from what I've seen) in that you can't run a custom Linux install on it to do much more than just serve up files.  But then, maybe that's why it's so fast!

Posted by Shane on February 27, 2006 10:23 PM | Permalink