The feature that I was most happy to see, however, was the NSL's built-in Backup. I nag every NAS vendor to bundle fully-functional multi-user backup capability with their product, since I think that this chore is the most dreaded and therefore least-performed essential maintenance activity.
I'm pleased to report that Linksys has exceeded my expectations in the NSL's Backup features and I think their implementation - plus the NSL's low pricing - will set the standard for competing products, as well as help them sell a lot of NSLs!
Figure 7: Backup features
Figure 7 shows the lower half of the Backup admin page (the upper half contains the NSL Configuration Save and Restore feature), which shows that the NSL features both Drive and Data Backup capabilities. The Drive backup isn't quite as good as RAID 5 mirroring, but at least ensures that as frequently as once a day, the entire contents of the NSL's Disk 1 will be backed up to its Disk 2.
This feature provides another layer of data security and I'd love to see it support using a USB 2 DVD burner as the second drive. This would provide even better protection against data loss by backing up data to removable media that could be stored off-site.
The really sweet feature, though, is the NSL's Data Backup. Figure 8 shows a backup job that I created for testing and shows most of the options available.
Figure 8: Backup job
In addition to the Full backup shown, you can also define Incremental and Synchronize jobs. Full backs up all files and Incremental backs up only changed files. A Synchonize backup will back up all files on its first run, then on subsequent runs delete any files on the destination drive that do not exist on the source (as well as backing up new files on the source drive).
A couple of positive points to note are that the Data Backup can handle shares that require a login, and lets you schedule multiple backups, which can run concurrently. You also can have the backup run from the NSL's drive to another networked share, which lets you back up a single-drive NSL.
I was able to emulate a Disk backup to removable media by creating a Data backup of the entire NSL Admin 1 share to a shared CD-RW on one of my networked machines. Not the cheapest way to do it, but it would get the job done!
There are, of course, other Backup features that I hope Linksys will add in future firmware releases. For starters, the NSL won't let you browse to pick the "Other device" used in the backup. Instead, you have to enter the full path to the share in "backslash" format, starting from the root of the share.
You also can't stop a backup once you launch it and the only progress monitor you get are job start and stop log entries, with not even an "in progress" indication in the NSL's Admin interface. You can see that something's up, though, from the flashing disk activity lights on the NSL and the USB drive. Finally, I'd definitely like to see some sort of backup report, even if it's only in summary form.
NOTE: During my backup testing I encountered a nasty bug that dampened my enthusiasm for this feature. What happens is that the NSL changes the File Modification Date/Time stamp on both the original and backup copy of each file that it backs up! The date gets changed to some time in 1970, which has the effect of blanking the Date Modified field in Windows Explorer's Details view. Viewing each file's properties, however, displays the modified incorrect 1970 date.
Linksys confirmed the problem - which is in the V2.3R21 firmware - and quickly turned around a new firmware revision that fixed the problem. But as of the time of this review Linksys has not yet posted it, nor any information regarding this bug's existence.
Update 7/7/2004 Linksys has posted Version 2.3 Release 24 that fixes this bug. Download from here.