PA views do not always record data for every sampling interval

[arndt]

I have some customer views setup in PA that have a View Sample Rate of 60 seconds.  When I look at this with "dfm perf view retrieve", I usually see a data point every minute.  However, I often see data points that are 2 to 3, or even 10, minutes apart. 

Is this because DFM was too busy to go out and ask the storage systems for performance data every minute?  Or are the storage systems not responding to DFM?  Other reasons?

Basically, I'm looking to understand the circumstances under which PA will not gather data at the designated View Sample Rate, so that I can avoid these circumstances and get the performance data gathered as desired the vast majority of the time.

Thanks!

Mike

[harish]

I haven't encountered such a scenario. Can you share the following details?

1. What is the object count of the customers? (dfm about would help)

2. What is the DFM version (Since you are using "dfm perf view

retrieve", I assume it to be earlier than DFM 4.0)

3. Are instances being added/deleted frequently in these setups? (When

instances change, the underlying files are re-written)

4. Has the customer configured a schedule for database backup? (When a

backup is being created, performance advisor is disabled)

5. Are you sure there are no intermittent communication issues with the

storage systems?

Regards

harish

[arndt]

We are running DFM 3.8...here is the dfm about output:

Version 3.8 (3.8)

Serial Number 1-50-001913

Administrator Name netapp

Host Name nerstrand

Host IP Address 167.68.252.149

Host Full Name nerstrand.int.westgroup.net

Operations Manager Node limit 125 (currently managing 81)

Provisioning Manager Node Limit 30 (currently managing 29)

Operating System SUSE Linux Enterprise Server 10

(x86_64) 2.6.16.60-0.21-smp x86_64

CPU Count 4

System Memory 7920 MB (load excluding cached memory:

47%)

Installation Directory /dfm/dfminst

38.6 GB free (15.7%)

Perf Data Directory /dfm/dfminst/perfdata

Data Export Directory /dfm/dfminst/dataExport

Database Backup Directory /dfm/dfminst/data/backup

Reports Archival Directory /dfm/dfminst/reports

Licensed Features Operations Manager: installed

Business Continuance Option: installed

Provisioning Manager: installed

Instances are added to these views at most once per day, and typically

less frequently than that.

Database backups are being run. We see no performance data during the

database backup, as we disable PA as part of this process, so that is

expected. I'm inquiring about periods of time outside of the database

backup.

I'm not aware of any communication issues with the storage

systems...would DFM log that somewhere if there were?

Thanks!

Mike

[harish]

If an incorrect password is set on a filer, messages similar to the

following will be logged in dfmserver.log file:

May 31 15:36:24 : : Remote function

calls to harish1 are failing due to incorrect credentials (using address

10.72.138.47 and username root). Check the hostLogin and hostPassword

host options.

Regards

Harish

[arndt]

Yes, but if we had an incorrect password, we would never get any

performance data, right? We are getting performance data, just not

always at the right sampling interval.

Mike

[harish]

Some more questions:

1. Are the sampling intervals and retention periods being modified in

the setup frequently?

2. Do you see this issue only for the custom views you created or

happens even for the canned views?

Regards

Harish

[arndt]

We are never modifying the sampling intervals or the retention periods

in these views. We see missing data points on the default views as well

as the custom views.

Mike