In our case, it's an exploding M$ Exchange Information store... It started
out on 2 36G disks, now it's up to 4. Mailbox quotas must be nice...
I was turned on to the wafl commands by one of our local PSE's last week, we
were having horrible performance reported while our Exchange snapshot
verifications were running. A statit showed 1 disk at 100% activity, and
the next one at 66%.
I ran a 'wafl scan measure_layout', and got:
wafl_filesystem_sca:info]: WAFL layout ratio for volume vol7 is 4.87. (A
ratio of 1 is optimal).
So, I run a 'wafl scan reallocate vol7', let it chug for an hour, then run
another 'wafl scan measure_layout', and it's still 4.87 :( I've done this
twice now, with no change in waffling. We're running 6.1.2.
At the advice of my PSE, I'm opening a ticket with NOW.
John Witham
Sr. Data Networking Engineer
Takeda Pharmaceuticals North America, Inc.
e://jwitham@takedapharm.com
V://847.383.3304
F://847.383.3205
A computer lets you make more mistakes faster than any invention in human
history, with the possible exceptions of handguns and tequila.
-Mitch Ratcliffe
-----Original Message-----
From: barry(a)lustig.com [mailto:barry@lustig.com]
Sent: Wednesday, January 23, 2002 12:15 PM
To: Matt Musgrove
Cc: Jeff Kennedy; NDMP List
Subject: Re: Repost: wafl scan question
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(a)amcc.com
>
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