On Wed, Oct 17, 2001 at 05:42:23PM -0400, dman wrote: > On Wed, Oct 17, 2001 at 01:49:01PM -0400, Paul McHale wrote: > | > | Does Linux support any RAM drive(s)? How much faster are these drives over > | an attached drive? Is there a CPU performance penalty? > > According to the kernel FAQ, Linux ext2 implementation is fast enough > that it is not necessary to implement /tmp as a ramdisk. Some systems > (they give stats, I think solaris is one of them) is much slower with > on-disk filesystems so Sun went with a ramdisk for performance with > temp files. I don't think you'll get much, if any, performance boost > from using a ramdisk. In the kernel config, look for "shm" (I think) > in the filesystem section. If you press "help" on it you'll see a > discussion of tmpfs (the other name for it). You can then mount it > with an entry in /etc/fstab. To enable a fixed-size ramdisk, you need to select CONFIG_BLK_DEV_RAM. To enable the "Virtual Memory Filesystem", choose CONFIG_TMPFS. The documentation is a bit confusing for this as it indicates that this filesystem is intended for POSIX shared memory, but it doesn't say you can't use it as a ramdisk. The relevant code is in mm/shmem.c Cheers, -- Nathan Norman - Staff Engineer | A good plan today is better Micromuse Ltd. | than a perfect plan tomorrow. mailto:nnorman@micromuse.com | -- Patton
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