Hi
We have a problem with our NFS server on Redhat 9. In case a program on the server uses high CPU, the NFS clients almost lock and nfs stops giving response until that program lowers its CPU usage. We tried to increase the priority of nfsd deamons with renice, and also tried to increase the number of nfsd threads, decreased the priority of the program using high CPU with renice, but none of them worked. How can we solve this problem so that nfs does not lock?
Yes, it is program that we wrote. It is doing some mathematical
calculations, so it utilizes full CPU. Other linux programs are not getting
very slow when this program runs, but client computers sometimes wait half a
minute in order to reach a file on nfs server. Logging in to the client
computers take around 10 minutes. Normally it takes no more than 20 seconds.
I mean nfs is almost locking, but no other linux program is badly affected.
At least we should be able to give better priority nfs via renice but we
couldn't figure it out. Doing renice -20 to all root programs didn't make
nfs faster.
----- Original Message -----
From: "Neil Horman" <[email protected]>
To: "Duv Dek" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, January 25, 2005 11:43 PM
Subject: Re: [NFS] NFS response time
> Duv Dek wrote:
>> Hi
>> We have a problem with our NFS server on Redhat 9. In case a program on
>> the server uses high CPU, the NFS clients almost lock and nfs stops
>> giving response until that program lowers its CPU usage. We tried to
>> increase the priority of nfsd deamons with renice, and also tried to
>> increase the number of nfsd threads, decreased the priority of the
>> program using high CPU with renice, but none of them worked. How can we
>> solve this problem so that nfs does not lock?
>>
> Have your tried to ascertain which process on your system is responsible
> (or most responsible) for the high CPU utilization?
>
> Neil
>
> --
> /***************************************************
> *Neil Horman
> *Software Engineer
> *Red Hat, Inc.
> *[email protected]
> *gpg keyid: 1024D / 0x92A74FA1
> *http://pgp.mit.edu
> ***************************************************/
>
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Duv Dek wrote:
> Hi
>
> We have a problem with our NFS server on Redhat 9. In case a program on
> the server uses high CPU, the NFS clients almost lock and nfs stops
> giving response until that program lowers its CPU usage. We tried to
> increase the priority of nfsd deamons with renice, and also tried to
> increase the number of nfsd threads, decreased the priority of the
> program using high CPU with renice, but none of them worked. How can
> we solve this problem so that nfs does not lock?
>
Have your tried to ascertain which process on your system is responsible
(or most responsible) for the high CPU utilization?
Neil
--
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*[email protected]
*gpg keyid: 1024D / 0x92A74FA1
*http://pgp.mit.edu
***************************************************/
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Duv Dek wrote:
> Yes, it is program that we wrote. It is doing some mathematical
> calculations, so it utilizes full CPU. Other linux programs are not
> getting very slow when this program runs, but client computers sometimes
> wait half a minute in order to reach a file on nfs server. Logging in to
> the client computers take around 10 minutes. Normally it takes no more
> than 20 seconds. I mean nfs is almost locking, but no other linux
> program is badly affected. At least we should be able to give better
> priority nfs via renice but we couldn't figure it out. Doing renice -20
> to all root programs didn't make nfs faster.
>
I assume that you included your program in the renice? If it still
didn't help, my immediate thought would be to enable nfsd_debug, try to
access the NFS share from a client, and check the message log. That
would at least tell you if the NFS server is receiving the NFS
transactions, and if so, where they might be taking the most time in
processing. That may give you a clue as to where the delay is comming
from, be it a scheduling delay from high CPU load, or contention on
another resource that is in short supply on your system.
Neil
>
>
> ----- Original Message ----- From: "Neil Horman" <[email protected]>
> To: "Duv Dek" <[email protected]>
> Cc: <[email protected]>
> Sent: Tuesday, January 25, 2005 11:43 PM
> Subject: Re: [NFS] NFS response time
>
>
>> Duv Dek wrote:
>>
>>> Hi
>>> We have a problem with our NFS server on Redhat 9. In case a program
>>> on the server uses high CPU, the NFS clients almost lock and nfs
>>> stops giving response until that program lowers its CPU usage. We
>>> tried to increase the priority of nfsd deamons with renice, and also
>>> tried to increase the number of nfsd threads, decreased the priority
>>> of the program using high CPU with renice, but none of them worked.
>>> How can we solve this problem so that nfs does not lock?
>>>
>> Have your tried to ascertain which process on your system is
>> responsible (or most responsible) for the high CPU utilization?
>>
>> Neil
>>
>> --
>> /***************************************************
>> *Neil Horman
>> *Software Engineer
>> *Red Hat, Inc.
>> *[email protected]
>> *gpg keyid: 1024D / 0x92A74FA1
>> *http://pgp.mit.edu
>> ***************************************************/
>>
>
--
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*[email protected]
*gpg keyid: 1024D / 0x92A74FA1
*http://pgp.mit.edu
***************************************************/
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
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_______________________________________________
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