Hello,
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"
Does anyone knows what is this process, its purpose, what happens if the system reboots during this,...
I'm asking this because on one system with lots of snapshots(snapvault) this process seems to never finish. In fact, each time a new snap is transfered the counter restarts from the beginning but has not enough time to finish until a new snapshot is created. Consequence : in snap status I see more and more snapshots with (xxx/xxx remaingint) on the right.
Thanks in advance for your answers!
Note that snap status is an advanced command so its output shouldn't necessarily cause you concerns... There is some metadata activity that occurs after a snapshot is created - the filer can reboot/crash in the middle with no harm since like anything on the filer this is a logged and consistent operation.
Eyal http://filers.blogspot.com
On 9/7/06, ec0li ecoli82@msn.com wrote:
Hello,
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"
Does anyone knows what is this process, its purpose, what happens if the system reboots during this,...
I'm asking this because on one system with lots of snapshots(snapvault) this process seems to never finish. In fact, each time a new snap is transfered the counter restarts from the beginning but has not enough time to finish until a new snapshot is created. Consequence : in snap status I see more and more snapshots with (xxx/xxx remaingint) on the right.
Thanks in advance for your answers!
View this message in context: http://www.nabble.com/Snap-status-and-wafl-scan-tf2232129.html#a6187160 Sent from the Network Appliance - Toasters forum at Nabble.com.
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@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 -
ec0li -
Eyal Traitel