From: Chuck Lever <chuck.lever@oracle.com>
To: Tom H <tom@limepepper.co.uk>
Cc: linux-nfs@vger.kernel.org
Subject: Re: why do attempts to access a nfs v3 filesystem (ro,soft) block the process for minutes at a time? (when the nfs server is down)
Date: Fri, 16 Jul 2010 12:26:18 -0400 [thread overview]
Message-ID: <4C40882A.2070203@oracle.com> (raw)
In-Reply-To: <4C408470.1090709@limepepper.co.uk>
On 07/16/10 12:10 PM, Tom H wrote:
> Chuck Lever wrote:
>> On 07/16/2010 11:20 AM, Tom H wrote:
>>>
>>> (also I noticed that it seems to timeout quicker with the mount options
>>> set like (soft, timeo=7, retrans=3) which is unexpected, because they
>>> are supposed to be the default)
>>
>> They are the default settings for UDP mounts, but you didn't specify
>> UDP. TCP is the default transport protocol, and has been for some
>> time. TCP uses a long retransmit timeout. See nfs(5).
>>
> OK, I see that now. Thanks.!
>
> However further experimentation with mount options
> (ro,soft,retrans=0,timeo=0,intr,proto=tcp) - requests to a failed nfs
> file-system still block the apache process for some apparently random
> time up to 3 minutes.
I don't know exactly what retrans=0 and timeo=0 might do, but short
timeouts over TCP are not recommended. If you want it to fail sooner
(and your network is clean enough), use proto=udp.
prev parent reply other threads:[~2010-07-16 16:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-16 15:20 why do attempts to access a nfs v3 filesystem (ro,soft) block the process for minutes at a time? (when the nfs server is down) Tom H
2010-07-16 15:25 ` Chuck Lever
2010-07-16 16:10 ` Tom H
2010-07-16 16:26 ` Chuck Lever [this message]
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