RELENG_5, snapshots and disk lock time

[Dmitry Morozovsky]

On Mon, 7 Mar 2005, Xin LI wrote:

XL> > dumping the snapshot of 140G ufs2 fyle system under contemporary RELENG_5 I 
XL> > found that during mksnap_ffs file system is unresponsible even for reading for 
XL> > more than 3 minutes (it's on modern SATA disk with 50+ MBps linear transfer). 
XL> > Is it normal?
XL> 
XL> mksnap_ffs is expected to suspend your write access, but I think 3
XL> minutes is too long for a 140G file system.  Would you please send the
XL> dumpfs output of the said file system?

Well, as I said, it was even for read access. I checked this with the simple 
shell script

#!/bin/sh

while true; do
	sleep 5
	date
	ls /lh/.snap
done

when dump -L executes mksnap_ffs for /lh, there is 3:20 pause between dates.

dumpfs output is available at http://woozle.hole.ru/misc/dumpfs-lh.gz (83k)

Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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