Linksys is no stranger to the low-end NAS business – it dabbled its corporate toes in these waters a year or so back with the entry-level EFG80. Recently it launched the Network Storage Link for USB 2.0 or NSLU2. It’s a NAS device sans any storage, which is down to you to provide – more ‘NA’ than ‘NAS’ in fact. Put simply, Linksys has yanked the firmware from the EFG80, given it a quick lick of polish and shoe-horned it in to a tiny solid-state Linux server, the size of a small modem. The result is an Open Source-based SAMBA server that converts any external USB drive to shared network storage.
The NSLU2 comes in a small form-factor case, with four status LEDs - Ready/Status and Ethernet, Disk 1 and Disk 2 link/activity. At the back is a pair of USB 2.0 ports and a 10/100Mbps Ethernet port. Inside is an embedded computer based on the Intel IXP420 Network Processor, backed by 8MB of flash and 32MB of RAM.
The two USB ports let you plug in a pair of external hard disk drives or a drive and a USB memory stick. The NSLU2 supports SMB (Server Message Block)/CIFS (Common Internet File System) over TCP/IP, which most modern OS’s support. This is a double-edged advantage. While it lets Linksys use free Open Source code for its NAS, it also means that it uses the Ext3 file system. In fact, as soon as you plug a USB drive into the unit, it will want to (re)format it, in toto, before it can be used.
As many external USB drives are used to swap data between Windows PCs, this means that the drive will be wiped clean before it can be used as network storage. And because it uses the Ext3 file system, only OSs based on Linux can access it directly – there’s no easy way for a Windows PC to access such a drive. You can’t even compromise by partitioning the drive as the NSLU2 only tolerates single partitions. So, once you connect a USB drive to the NSLU2 you may as well consider it to be internal. Disk drives are not hot swappable, so you must first power down the unit before connecting or disconnecting one. Which all rather negates the raison d’etre of highly portable external USB drives.
If this state of affairs doesn’t suit you, there’s nothing to stop you from amending the NSLU2’s firmware as the CD-ROM includes the original source for the SnapGear Embedded Linux that the NSLU2 runs on. Indeed several sites on the web have taken great delight in ‘repurposing’ the NSLU2 with hacked code.
Setting up the NSLU2 is simple enough. You can use the supplied setup wizard to locate it or you can cut to the chase, fire up a browser and surf over to 192.168.1.177, the default IP address of the NAS. It includes a DHCP client but keeping a static IP address is probably best. Its default security settings are a bit lax and it’s probably a good idea to avoid exposing it to the ravages of the WAN before changing the default password and altering the default access port of 80 to something else. HTTPS/SSL isn’t supported either.
Linksys has struck some sort of co-marketing deal with Maxtor and recommends pairing the NSLU2 with a Maxtor OneTouch though if you do, the famous blue ‘backup now’ button on the drive will become redundant. Formatting a 160GB OneTouch drive doesn’t take long, less than a quarter of an hour. Although you can plug in USB flash memory, USB optical storage isn’t supported. It’s possible to schedule systems shutdowns and startups but you can’t control the attached USB drive.
By default two default folders or shares are set up, Disk 1 and Admin 1, the latter being restricted to the Administrator. Sadly, permissions granularity is not particularly fine – file or user-level permissions aren’t supported. Users can also be assigned to Groups and have Disk Quotas assigned in 1MB increments. Unfortunately, its not possible to check how much of a user's storage quota has been consumed — you only find out that you're over when the attempt to save a file fails.
The NSLU2 is lacking in a couple of areas. It isn’t possible to disable HTTP access to the USB drives, nor can you set a different port for admin and file access. FTP file access is not supported. Event logging is very basic. It’s easy, however, perform backups between two devices plugged in the NSLU2. A good range of backup options is, however, provided.
Speed is not the NSLU2’s forte it has to be said. USB 2.0 may have a 480Mbps bandwidth but this has to pass down 100Mbps Cat5. As a result you’ll typically see read and write speeds no faster than about 10 and 12MBps respectively, a tiny fraction of what a USB 2.0 is capable of when connected directly.
NAS devices are a good way to add storage to a network without the costs and hassles of upgrading a general-purpose server. But while NAS devices can be considerably cheaper than such servers, they can still be pricey for a small business, easy to outgrow and hard to upgrade. The NSLU2 is a cheap way for SMEs to get on the potentially fraught NAS bandwagon. You get a simple SAMBA server with an easy to use UI and good backup facility. Plug in a pair of cheap 250GB USB 2.0 drives and you’ve got a heap of cheap network storage on tap. The NSLU2 isn’t perfect by a long chalk – it’s slow and tends to nail down USB drives to the spot. It also lacks some features but nothing that a few firmware upgrades can’t fix.