[net.unix] 4.2 File System Tuning

marc@aplvax.UUCP (Marcus H. Gates) (08/06/85)

    Investigating our SLOW 4.2 system and grasping at straws led me
to discover a discrepancy between the documented default value for
fs_rotdelay and the actual default value used when creating a filesystem.

fs(5) says that the default is 2ms while looking at mkfs.c shows that the
value used is 4ms (this fact was also verified using dumpfs). Is 2ms 
better than 4??? Our disks are SI9766's emulating rm05's. Any help
in correctly tuning our filesystems is appreciated.
-- 
					marc gates
					umcp-cs!aplvax!marc

chris@umcp-cs.UUCP (Chris Torek) (08/07/85)

I dunno about 9766s, but I set the rotdelay to 1ms on our 785 w/
massbuss Eagles -- it gave the best numbers of all the things I
tried (1..20 I think it was).

I couldn't get any significant variation at all on our 750s w/ RA81s.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@maryland