KCASSIDY@STMARYS.BITNET ("Kevin Cassidy, System Operator") (01/12/88)
About the RAM Disk for VAXes. We have a MicroVAX II running one of these RAM Disks and so far we've had no problems. There is no documentation as someone has pointed out. We found out how to set up the ramdisk by looking over one of the files that comes with MicroVMS. In SYS$UPDATE the file STABACKIT.COM contains the DCL commands and routines needed to set up the ramdisk. This is for systems who wish to build standalone backup to TK50's (the uVAX standard tape drive). Once extracted from the command file, it is very easy to build and maintain your own ramdisk. The only stipulation is that you have adequate memory available and are willing to change some system parameters (such as NPAGEDYN) (only through MODPARAMS.DAT of course!!!!) As for applications, our startup file currently builds the ramdisk, creates appropriate directories and moves files off the hard disk to the ramdisk. We also have a background process which backs up the ramdisk to hard disk every half hour (just in case even though we have a UPS!). I would certain like to hear about any other information I might have missed as we are also relatively new to this (about a year now). ================================================================================ Kevin Cassidy Programmer/Operator St. Mary's University (902) 420-5476 BITNET: KCASSIDY@STMARYS ================================================================================
hydrovax@nmtsun.nmt.edu (M. Warner Losh) (01/15/88)
Ram disks on VMS are a waste. At lest the one that have been in the
distributions. They are slower than disks are, they steal memory from
EVERYBODY and they are unsupported. If you don't have very many
users and they all are running TINY codes, then maybe it might
be kinda sorta worth it. At the very least you should get the patches
that have been floating around on this newsgroup (or mailing
list or whatever your means of reading it is). They help
preformance a lot.
One thing that you SHOULD NOT EVER EVER EVER EVER EVER EVER
EVER do, is to use a RAM disk for swap space. Think about what is
happening here, you are stealing memory from processes do you can
swap at about the same speed. Wouldn't it be a little smarter to
put the swap space on the disk and use the memory for larger
working sets?
--
bitnet: lush@nmt.csnet M. Warner Losh
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