What 2.5" hard drives are suitable
From Soekris Info Wiki
Soekris sells mounting kits for 2.5" hard drives, which include a mounting bracket, standoffs and a short signal cable. net4801 supports PATA. net5501 supports PATA or SATA (this is connected by a bridge to PATA; you can't use both ports and a CF; it is possible to use one PATA and one SATA drive together with a workaround). For DMA support on net5501, use comBIOS 1.32i or newer, and a recent OS release.
If you're going to run 24*7, then you probably want to be running a drive designed for that purpose. Most laptop drives spend much of their lives either switched off or spun down to save the laptop battery and are not rated for continuous operation. Ordinary laptop drives may fail prematurely if you use them for a server application.
Some Hitachi 2.5 inch drives rated for 24*7 use are:
- Travelstar E7K100 (SATA and PATA);
- Travelstar E5K160 (SATA and PATA);
- Travelstar E5K250 (SATA only).
See www.hitachigst.com (Products, Travelstar).
Update (March 2009): In the UK, Dabs.com now stocks the Travelstar 5K320 EA (Extended Availability) drive: 320GB @5400 RPM. Hitachi part number HTE543232L9A300, Dabs part number 5H0QTS. Rated for 24*7 operation. (A 500 GB version has also been announced: if anyone finds these in stock somewhere, please update this page.)
Unlike laptop drives, these Hitachi drives do not keep spinning up and down when idle: they just keep spinning the whole time. The rationale is that this makes for greater stability, but power consumption is still very low. So it seems like a good match for a low-power Soekris server.
It's usually possible to configure laptop drives not to spin down; on OpenBSD this is done with the apmset option to atactl(8).
Three Fujitsu drives to consider are:
- MHW2120BK - high duty cycle (newer);
- MHV2080BS - high duty cycle (older and near eol);
- MHW2040AC - extreme environment (automotive).
In warm environments, you may need to fit a small fan inside the case to keep the hard drive cool. High drive temperatures greatly increase the risk of drive failure. A fan running at even a low speed can greatly reduce temperatures. Drive temperature can often be monitored via SMART; smartmon is available on most open-source OS and supports temperature measurement on a wide range of drives. Note that Smartmon should not be set to perform automatic offline testing on a live server (so take care to override the default config file on the FreeBSD port of Smartmon): this is known to cause occasional ATA device driver timeouts in the FreeBSD kernel, and may reduce the useful life of the drive.
If you'd like to purchase a high duty cycle drive, it might be necessary to look for a storage specialist; they are often not carried by general-purpose PC hardware suppliers.
