cancel
Showing results for 
Search instead for 
Did you mean: 

Fc _%util =100%

Semmar_2
Occasional Visitor

Fc _%util =100%

Hi all

We 'are using sar -H to check FC HBA activity on our servers . Even ,we 're not facing performance issue for now ,sar -*H shows 100% in %util .. but 0 ms in avwait and 2 ms in avserv .

Would you please help

Regards
Mohamed

7 REPLIES
Turgay Cavdar
Honored Contributor

Re: Fc _%util =100%

What about the other values (in fact they are the important ones) t-put IO/s r/s w/s ?
Suraj K Sankari
Honored Contributor

Re: Fc _%util =100%

Hi,

Read man pages of sar.

Suraj
Semmar_2
Occasional Visitor

Re: Fc _%util =100%

Dear all

Please find attached sar -H 1 60 output . (averages )
Of course , sar man pages is not enough to understand 100% util & 0 ms avwait

Is it a trusted way to probe FC activity ?

Regards

Turgay Cavdar
Honored Contributor

Re: Fc _%util =100%

Hi,
On your db server nearly 3000 IO is done on each HBA(this is a high value actually). These are all read activity, we can say this is OLTP, IO size is 8K. In SAN environments there is no way to see the actual performance state of the storage so busy value is not a true performance indicator. The real values you need to take care is service time and avque. It seems good for you from your outputs.
Semmar_2
Occasional Visitor

Re: Fc _%util =100%

Many thanks Turgav

Indeed ,main CI(SAP ) is running there ,and
although 100%Util seems fake , we 're planning to allocate two more FCs .(vPar!)

Do you think '% util' will decrease to half ? is it linear ? Any advice there






Turgay Cavdar
Honored Contributor

Re: Fc _%util =100%

Hi,
As i said before busy value is not a true performance indicator because from hp-ux we cannot see what happens beyond the storage cache and to the actual disks. So you need to add additional FC card? Look at service time and disk queues if thet are at acceptable values then it means they can do more IO. Another thing you can look is your FC card max IOPS and storage performance values.
Semmar_2
Occasional Visitor

Re: Fc _%util =100%

Ok .
Many thanks & regards