On Aug 10, 2009, at 4:05 PM, Carlos André wrote:
Something funny: Using default tcp_syn_retries (5) i got
"3,6,12,24,48,96" secs interval... but if i change tcp_syn_retries to
1 i got "3,6,3,6,3,6..." secs interval...
Right. Normally the RPC client calls the kernel's socket connect
function, which does 6 SYN retries. That one call usually takes
longer than the RPC client's connect timeout, so it only makes one
connect call, and then fails.
Reducing the number of SYN retries per connect attempt causes the RPC
client to retry the connect call until its connect timeout expires.
Each connect call resets the SYN timeout to 3 seconds.
[root@KSERVER mnt]# time mount 1.2.3.4:/blabla tmp/ -t nfs4 -o
sec=krb5p,proto=tcp
mount: mount to NFS server '1.2.3.4' failed: timed out (giving up).
real 3m9.000s
user 0m0.000s
sys 0m0.002s
[root@KSERVER /]# echo 1 > /proc/sys/net/ipv4/tcp_syn_retries
[root@KSERVER mnt]# time mount 1.2.3.4:/blabla tmp/ -t nfs4 -o
sec=krb5p,proto=tcp ("retry=1" = no change)
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (retrying).
mount: mount to NFS server '1.2.3.4' failed: timed out (giving up).
real 2m6.004s
user 0m0.000s
sys 0m0.004s
(3,6,3,6... secs interval)
2009/8/10 Carlos André <candrecn@xxxxxxxxx>:
No, i'm just using packages from CentOS repo...
And u're right about expo retries... with tcpdump i've monitored
traffic and i got SYN retries in 3, 6, 12, 24, 48, 96 secs on port
2049...
I tried use "retry=1" option on mount without any change... I dont
want change source or tcp timers... just NFSv4 client.
2009/8/10 Chuck Lever <chuck.lever@xxxxxxxxxx>:
On Aug 10, 2009, at 2:29 PM, Carlos André wrote:
Bruce, no... you're right. I'm describing a situation where my
server
died... i need mount fail faster (10 or 15 secs max) than 3 minutes
and 9 seconds...
The 189 second timeout is likely how long it takes the kernel to
give up
trying to connect a TCP socket to the server (6 SYN attempts with
exponential retries, or something like that). For stock CentOS
5.3, I think
user space does only a DNS lookup for normal NFSv4 mounts -- the
kernel just
tries to connect a TCP socket to port 2049, with no preceding
rpcbind
request.
Carlos, let us know if you have replaced any NFS-related CentOS
components
(kernel, nfs-utils) with something you've built yourself.
2009/8/7 J. Bruce Fields <bfields@xxxxxxxxxxxx>:
On Fri, Aug 07, 2009 at 09:42:18AM +0300, Benny Halevy wrote:
On Aug. 07, 2009, 3:18 +0300, Carlos André <candrecn@xxxxxxxxx>
wrote:
Anyone ?
2009/7/29 Carlos André <candrecn@xxxxxxxxx>:
PPL, I need put a CentOS 5.3 (updated) NFSv4 server to work
with
Kerberos
and AutoFS, but i got a problem: If NFS server goes down i
get a
LOOOOOOONG
mount timeout on CentOS 5.3 (updated) NFSv4 client...
Since i need mount some (3 to 6) dirs at user logon process,
if mount
hangs,
user logon hangs. Then i want configure it to timeout (if
server down)
after
10-15 secs (MAX) on each mount attempt.
I already make a lab and tried a LOT of combinations, there my
findings
(server DOWN IP: 172.16.0.10 / client IP: 172.16.1.10) using
basic
command
(time mount 172.16.0.10:/remotedir /localdir/ -t nfs4 -o
sec=krb5,proto=<tcp/udp>) from NFS client:
- Once i try access mount point using AutoFS (proto=tcp OR
proto=udp)
it
hangs for 189 secs (3m9s: real 3m9.001s) until show error
(mount:
mount to
NFS server '172.16.0.10' failed: timed out (giving up))
Sounds like you're hitting the server's grace period.
I thought he was describing a situation where the server the
server
is completely gone and isn't coming back, and wondering how to
make the
mount fail faster. But I may be misunderstanding.
--b.
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--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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chuck[dot]lever[at]oracle[dot]com
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