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		GETTING A FASTER BOOT UP WITH MULTIPLE DISKS

SunFLASH Vol 12 #19					 December 1989 
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	OR HOW TO IMPRESS A CUSTOMER COMPLAINING OF LONG BOOT TIME
		DUE TO SIX 892MB DISK DRIVES RUNNING FSCK

(this is a tip from a Sun field engineer - johnj)

For those with multiple disks who can't stand to wait all day for 
fsck to finish gigabytes of file check, there is a happy solution.
You must modify the /etc/fstab file.  The last number in each line
is the order in which fsck is performed.  Suninstall sets these numbers 
up sequentially but the fsck's can be performed simultaneuosly on different
disks.
	Always have your root partition, i.e. xy0a, be the only line that
ends with 1.  The rest of the partitions on that disk go 2,3,4 etc.
Each successive disk can also be done 2,3,4 etc.  This has the effect of 
allowing root to be checked first and alone in case of the need to reboot
itself (so that the other file checks don't get aborted if there are errors
in root), and the rest of the partitions get checked next, i.e. all the 2's,
all the 3's, etc.
	The processor is quite capable of handling multiple fsck's, just
make sure that the same disk does not have two last numbers the same.  The
seeking back and forth between partiitons of the same disk will cause an
increase in fsck time, not an improvement.
	The overall effect of this method is that the entire fsck process
during boot only takes as long as the largest disk alone.  The following is
a sample fstab:

/dev/xy0a / 4.2 rw,nosuid 1 1
/dev/xy0g /usr 4.2 rw 1 2
/dev/xy0e /ipc 4.2 rw 1 3
/dev/xy0f /data 4.2 rw 1 4
/dev/xy0d /var 4.2 rw 1 5
/dev/xy0h /home 4.2 rw 1 6
/dev/xy1d /extra0 4.2 rw 1 2
/dev/xy1e /extra1 4.2 rw 1 3
/dev/xy1f /extra2 4.2 rw 1 4
/dev/xy1g /extra3 4.2 rw 1 5
/dev/xy1h /extra4 4.2 rw 1 6
/dev/sd0d /usr1 4.2 rw 1 2
/dev/sd0e /usr2 4.2 rw 1 3
/dev/sd0f /usr3 4.2 rw 1 4
/dev/sd0g /usr4 4.2 rw 1 5
/dev/sd0h /usr5 4.2 rw 1 6
/dev/sd1d /data1 4.2 rw 1 2
/dev/sd1e /data2 4.2 rw 1 3
/dev/sd1f /data3 4.2 rw 1 4
/dev/sd1g /data4 4.2 rw 1 5
/dev/sd1h /data5 4.2 rw 1 6

THIS CAN BE A REAL TIME SAVER WHEN PROPERLY APPLIED

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Sunflash is an electronic mail news service from Sun Microsystems,
Ft. Lauderdale, FL. Please address comments to John McLaughlin
(sun!sunvice!johnj or johnmclaughlin@sun.COM). (305) 776-7770.