I have recently been investigating the suitability of small 2.5" pocket disk drives in a 24/7 application as the main drive on an Arm (Pogoplug, Dockstar, etc.) server. These drives are nice to use because they are self-contained, take little power, and require only one connection to the outside world -- the USB cable. I have one such server which I set up in January using an old Western Digital 160GB pocket drive I had lying around. It has worked flawlessly, but the drive itself seemed to make a slightly worrysome reset sound on a regular basis. With the aid of the smartmontool smartctl, I noticed the drive was racking up a huge number of Load_Cycle_Count events. Further investigation (via Google) revealed that this drive, like many pocket drives, is designed to park the heads by default if the drive has not been accessed for 5 seconds. This may make sense in a typical applcation where the drive is subject to being physically knocked around, but Unix on a quiescent box has background tasks which can still result in disk accesses several times a minute. In a server application, the net result is that the heads are constantly being parked and unparked. The drive keeps tabs on how many times this occurs and the smartctl command can be used to view this and other data. In approximately 3 months of run time, my little WD drive had parked and unparked its heads over a quarter million times, and most drives are lifetime speced at 300-600k head parks. Thus, these drives could easily exceed their lifetime design in the respect in well within a year of normal use.
One solution is to forego the use of these pocket drives in this application. A conventional 3.5" drive in an external enclosure will typically not have this sort of programming. Another option is to turn off this head-parking function in the drive. The most recent smartctl program has a facility to do this, but unfortunately, the version packaged with Debian Squeeze and Wheezy predates the addition of this code. It is fairly straightforward to download the latest smartmontools tarball from sourceforge and compile your own copy, though.
My question: Is anyone else here using 2.5" portable drives as their storage device on their Plug servers? If so, what sort experience have you had with these drives? Have you taken any steps to deal with this problem? Finally, it's late here, but if people are interested I can give you more specific details at a later point in time as to how I've worked around this problem. But, I'm mainly curious whether others have seen any problems with these small drives in the application.
YMMV.
One solution is to forego the use of these pocket drives in this application. A conventional 3.5" drive in an external enclosure will typically not have this sort of programming. Another option is to turn off this head-parking function in the drive. The most recent smartctl program has a facility to do this, but unfortunately, the version packaged with Debian Squeeze and Wheezy predates the addition of this code. It is fairly straightforward to download the latest smartmontools tarball from sourceforge and compile your own copy, though.
My question: Is anyone else here using 2.5" portable drives as their storage device on their Plug servers? If so, what sort experience have you had with these drives? Have you taken any steps to deal with this problem? Finally, it's late here, but if people are interested I can give you more specific details at a later point in time as to how I've worked around this problem. But, I'm mainly curious whether others have seen any problems with these small drives in the application.
YMMV.