Ok - those are other things than what I previously mentioned.
Active Bitmap rearrangement is normal - I believe it has been around
since 6.5 (pretty sure it wasn't a flexvol thing, that was 'deswizzler'
scan). It's to keep memory 'pretty', if memory serves.
The container block reclamation is a scanner responsible for ferreting
out blocks that have been freed and marking them as usable to the system
(delayed free scanner\delayed freer working here). This too is normal.
Glenn
-----Original Message-----
From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com]
On Behalf Of Chris Thompson
Sent: Thursday, September 07, 2006 4:01 PM
To: toasters(a)mathworks.com
Cc: ecoli82(a)msn.com; etraitel(a)gmail.com
Subject: Re: Snap status and wafl scan
Eyal Traitel writes:
> Note that snap status is an advanced command so its output shouldn't
> necessarily cause you concerns...
Well, while we're talking about things wot mere mortals were not meant
to wot of...
ec0li <ecoli82(a)msn.com> wrote:
> When I check snap status, I see next to recent snapshots : (xxxx/xxxx
> remaining).
> Also, It seems that this is in fact the wafl scan process "snap create
> summary update"
The effect worrying me is somewhat different. After a snapshot is
deleted
the above state lasts only seconds, but there is then a much more
extended
period where "snap status" looks normal but "wafl scan status" shows
e.g.
carina*> wafl scan status
Volume CUS:
Scan id Type of scan progress
1 active bitmap rearrangement fbn 3340 of 4461 w/
max_chain_len 3
925 container block reclamation block 382 of 4461
The "container block reclamation" scan lasts several minutes (and this
is
a volume & aggregate of only a few hundred GB), and while it's going on
disc read activity is high and severely impacts the cache - at least, if
you trust the "cache age" shown by sysstat, which I am not sure I do.
This is with ONTAP 7.1.1P1 (but similar effects observed in earlier
7.x's).
--
Chris Thompson
Email: cet1(a)cam.ac.uk