ajudge@maths.tcd.ie (Alan Judge) (08/12/90)
I have an SS1 with a Fujitsu M2263S-512 (655Mb) drive attached; the drive supports read-ahead caching, which I have enabled. What I would like to know is whether it is worth adjusting file systems on the drive with tunefs to take advantage of this cache? Has anybody any experience with caching drives and tuning? I can try experimentation, but it would be easier if someone else already has tried this. Mail me and I will summarise to the net. On another subject, has anyone managed to get any SCSI drive to work in synchronous mode with a SPARCStation? Alan Judge ajudge@maths.tcd.ie a.k.a. amjudge@cs.tcd.ie +353-1-772941 x1782
gibson@uunet.uu.net (08/14/90)
In article <1990Aug13.011415.6197@rice.edu> you write: >I have an SS1 with a Fujitsu M2263S-512 (655Mb) drive attached; the drive >supports read-ahead caching, which I have enabled. What I would like to >know is whether it is worth adjusting file systems on the drive with >tunefs to take advantage of this cache? > >Has anybody any experience with caching drives and tuning? It has been our experience that you can get excellent (sequential) read performance by turning on read-ahead and setting rotational delay (via tunfs) to 0ms. Sadly, the write performance goes way down. I believe that with a new driver, called by some a "low level scatterer-gatherer" the write performance would return to normal. With SCSI II drives becoming available now the read-ahead parameters are getting very confusing. - number and/or size of segments - read/write retention priority - max/min prefetch - cross cylinder boundary enable - etc