RELENG_5, snapshots and disk lock time

Dmitry Morozovsky marck at
Mon Mar 7 07:00:57 PST 2005

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> 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


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

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

dumpfs output is available at (83k)

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

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