What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
Don't know if this didn't get through or what so I'm reposting.
Thanks.
Jeff Kennedy wrote:
What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
jlkennedy@amcc.com (Jeff Kennedy) writes
Jeff Kennedy wrote:
What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
[...]
Don't know if this didn't get through or what so I'm reposting.
Thanks.
It got through all right, but as "wafl scan" is an advanced mode command with no public documentation, perhaps you shouldn't have been too surprised that no-one has been able to reply to it yet ... Most of us probably didn't even know that it existed!
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QH, Phone: +44 1223 334715 United Kingdom.
From my ONTAP course notes:
wafl scan reallocate takes a volume or file and reallocates it on the disk to increase its layout efficiency (ie. defrags). However, you should only run this command on the advice of NetApp. It should only be run if volume capacity is <80% and during a non-peak period (filer impact similar to a vol copy command).
hope that helps
Matt Musgrove
Jeff Kennedy wrote:
Don't know if this didn't get through or what so I'm reposting.
Thanks.
Jeff Kennedy wrote:
What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
--
Jeff Kennedy Unix Administrator AMCC jlkennedy@amcc.com
That's it, thanks.
~JK
Matt Musgrove wrote:
From my ONTAP course notes:
wafl scan reallocate takes a volume or file and reallocates it on the disk to increase its layout efficiency (ie. defrags). However, you should only run this command on the advice of NetApp. It should only be run if volume capacity is <80% and during a non-peak period (filer impact similar to a vol copy command).
hope that helps
Matt Musgrove
Jeff Kennedy wrote:
Don't know if this didn't get through or what so I'm reposting.
Thanks.
Jeff Kennedy wrote:
What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
--
Jeff Kennedy Unix Administrator AMCC jlkennedy@amcc.com
This sounds like it would be useful for volumes that started out with low performance needs with a small number of disks in the array that ended up with large raid sizes. I imagine that files would get striped across the larger number of drives after the reallocate.
barry
On Wednesday, January 23, 2002, at 02:00 AM, Matt Musgrove wrote:
From my ONTAP course notes:
wafl scan reallocate takes a volume or file and reallocates it on the disk to increase its layout efficiency (ie. defrags). However, you should only run this command on the advice of NetApp. It should only be run if volume capacity is <80% and during a non-peak period (filer impact similar to a vol copy command).
hope that helps
Matt Musgrove
Jeff Kennedy wrote:
Don't know if this didn't get through or what so I'm reposting.
Thanks.
Jeff Kennedy wrote:
What exactly does 'wafl scan reallocate' do? Does it actually re-write data in a more efficient manner/layout? Or does it redo inodes and pointers in a more efficient layout without moving data?
I know that a reallocate is unnecessary if the measure_layout is low (most of mine are under 2) but on occassion I get higher numbers and wonder what it does to fix this.
Thanks.
--
Jeff Kennedy Unix Administrator AMCC jlkennedy@amcc.com
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barry＠lustig.com -
Chris Thompson -
Jeff Kennedy -
Matt Musgrove