Dave Close wrote: > I know you guys are discussing servers with hard disks, but what are > your thoughts about systems without disks, so-called embedded systems? > Embedded these days doesn't mean small and probably does mean they are > running a general purpose OS like Linux. I use some with a couple of GB > of RAM, but their only "disk" is flash. Writing to flash is not only > slow but also invokes the wear-leveling algorithms and, ultimately, > reaches the point where the flash is worn out. One tries to avoid any > writes. The smaller the "swap" space, the more concentrated the writes. > So, if you say that a system without any "swap" misbehaves, how does a > system like this survive? > I'm not sure why you say that flash is slow. Any recent flash, say the last 2 years, is MUCH faster than spinning media in all dimensions. For example, try putting a ZIL (ZFS intent log) on flash media and watch your NFS meta-data operations go from moribund to zoom. Wear levelling is a concern but is becoming less of one over time. Sun is partnering with a vendor on flash with 1 million write cycles. If you have that and a 30 or 80GB flash, it would last years even under relatively hostile circumstances.
Today, I wouldn't put swap on a flash drive (depending on the app), but I might in a year. Slow is yesteryear's flash. _______________________________________________ Discuss mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
