NetApp Sysstat CP Type

The CP type will give you important information about the health of the ability of the system to write.

Basically, you want to avoid Bs and bs.  B means bad.  B means back to back CP, which means the disks can't keep up with the write workload.

B = Bad

b = even more bad

If you have a B or a b, you need more disks in the aggregate to be able to keep up with the writes.

CP Ty : Consistency Point (CP) type is the reason that a CP started in that interval. The CP types are as follows:

• - No CP started during sampling interval (no writes happened to disk at this point of time)
• number Number of CPs started during sampling interval
• B Back to back CPs (CP generated CP) (The filer is having a tough time keeping up with writes)
• b Deferred back to back CPs (CP generated CP) (the back to back condition is getting worse)
• F CP caused by full NVLog (one half of the nvram log was full, and so was flushed)
• H CP caused by high water mark (rare to see this. The filer was at half way full on one side of the nvram logs, so decides to write on disk).
• L CP caused by low water mark
• S CP caused by snapshot operation
• T CP caused by timer (every 10 seconds filer data is flushed to disk)
• U CP caused by flush
• : continuation of CP from previous interval (means, A cp is still going on, during 1 second intervals)

The type character is followed by a second character which indicates the phase of the CP at the end of the sampling interval. If the CP completed during the sampling interval, this second character will be blank. The phases are as follows:

• 0 Initializing
• n Processing normal files
• s Processing special files
• f Flushing modified data to disk
• v Flushing modified superblock to disk

CP util : The Consistency Point (CP) utilization, the % of time spent in a CP.  100% time in CP is a good thing. It means, the amount of time, used out of the cpu, that was dedicated to writing data, 100% of it was used. 75% means, that only 75% of the time allocated to writing data was utilized, which means we wasted 25% of that time. A good CP percentage has to be at or near 100%.