2010-11-11 05:17 PM
Attached is the output from sysstat in one second intervals. Looking at the column for the cache age I noticed that some values have the letter "s" tagged on the end. Does anyone know what the significance of that is?
This filer is running NetApp Release 7.3.3P4 it is a Nearstore Primary filer and has the "nearstore_option" license along with the "a_sis" license
2010-11-11 10:56 PM
This post was made by a student of mine, in class.
If it means 'seconds', then why does it trip in and out again ?
I haven't looked into the xml files for presets yet, but ...
My best guess was that it was 'system' buffers swapped out of cache ... ?
Do we have a pro from Dover here who can tell us why it is on some lines, but not others ?
We figured out why there is a jump - it's in the age of cache pages retired.
(As documented in the System Administration Guide)
We could not find this in the docs, though we all tried hard as a team effort in class today ...
I hope this response has been helpful to you.
At your service,
(P.S. I'm sure this student will give points for helpful or correct answers.)
2010-11-11 11:43 PM
I learn new things every day - It's why I love my job.
From the 'Data ONTAP System administrtion Guide':
(Which most often bores me = it's sooo old hat.)
System Performance and Resources -> How to Increase WAFL cache memory
It describes that the sysstat cache age is the age of blocks swapped out of cache. I always described it as the average age of objects in cache.
There is a distinct diference, due to the intelligent cache algorithm used in ONTAP.
It changes, over time based on many factors,
(nearstore, FlexShare, PAM)
Best guess I gave studfent - 's' might mean 'system' buffers aged out of cache.
But sometimes the documentatikn can be thin 'round here.
Is there someone from engineering who might clarify for us ?
I hope this response has been helpful to you, others, and to Terry. (Go Notre Dame!)
At your service,
Eugene E. Kashpureff
Fastlane NetApp Instructor and Independent Consultant
(P.S. I appreciate points for helpful or correct answers.)