[OpenAFS] PriorityClass registry setting in windows OpenAFS client

Lobaugh, John John.Lobaugh@morganstanley.com
Tue, 4 May 2010 13:06:01 -0400


Thanks so much for your detailed answer. This helps. The windows =
engineering team here is currently testing Currently we are =
locked down to 1.4.2 for production servers until they sign off on the =
new version. I guess we will have to live with it until we can get the =
new release installed on our machines. In the interim I will check to =
see if we have the patched Mrxsmb.sys on our servers.=20


-----Original Message-----
From: Jeffrey Altman [mailto:jaltman@secure-endpoints.com]=20
Sent: Tuesday, May 04, 2010 11:26 AM
To: openafs-info@openafs.org
Cc: Lobaugh, John (IT)
Subject: Re: [OpenAFS] PriorityClass registry setting in windows OpenAFS =

On 5/4/2010 10:56 AM, Lobaugh, John wrote:
> =20
> Is the reg setting
> =20
> HKLM\SYSTEM\CurrentControlSet\Services\transarcafsdaeomon/PriorityClas
> s
> =20
> used with version  of the Windows AFS service ?

PriorityClass is not present in the 1.4.2 distribution.

> We have been struggling with a deadlock issue on two Windows 2003=20
> servers where this setting is not present. The issue is not occuring=20
> on some other servers where the setting is present.
> =20
> John Lobaugh

Windows Server 2003 with SP2 applied with deadlock in the SMB redirector =
if http://support.microsoft.com/kb/969289 is not installed.  In tracking =
down the source of these deadlocks with Microsoft numerous changes where =
made to the OpenAFS client to improve its compatibility with Microsoft's =
SMB client.  These first appeared in the 1.5.59 release.

The present release is 1.5.74 which had many more significant changes =
including corrections to the Rx library errors that were causing RPCs to =
timeout and be retried putting additional stress on Microsoft's SMB =

The SMB client has a limited number of worker threads, 10 to be precise.
 If all 10 workers are in use and communicating with the same SMB =
server, for example \\AFS, then if one of the workers decides that the =
connection must be broken and re-established, there is no free worker =
thread to perform the queued request.  It is at this point that a
deadlock occurs.   The changes made in the KB969289 hotfix to the SMB
redirector is to extend the timeout period from 45 seconds to several =
minutes.  It is still up to the AFS SMB server to make sure that a =
response is sent in time.  Otherwise, a deadlock can occur.

If you can, please use the latest OpenAFS client.  1.4.2 is ancient =

Jeffrey Altman

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