Hi Salvatore,

Are you using ethernet or infiniband as the GPFS interconnect to your clients?

If 10/40GbE - do you have a separate admin network?

I have seen behaviour similar to this where the storage traffic causes 
congestion and the "admin" traffic gets lost or delayed causing expels.

Vic



On 21 Aug 2014, at 10:04, Salvatore Di Nardo <[email protected]> wrote:

> Thanks for the feedback, but we managed to find a scenario that excludes 
> network problems.
> 
> we have a file called input_file of nearly 100GB:
> 
> if from client A we do:
> 
> cat input_file >> output_file
> 
> it start copying.. and we see waiter goeg a bit up,secs but then they flushes 
> back to 0, so we xcan say that the copy proceed well...
> 
> 
> if now we do the same from another client ( or just another shell on the same 
> client) client B :
> 
> cat input_file >> output_file
> 
> 
>  ( in other words we are trying to write to the same destination) all the 
> waiters gets up until one node get expelled.
> 
> 
> Now, while its understandable that the destination file is locked for one of 
> the "cat", so have to wait ( and since the file is BIG , have to wait for a 
> while), its not understandable why it stop the renewal lease. 
> Why its doen't return just a timeout error on the copy  instead to expel the 
> node? We can reproduce this every time, and since our users to operations 
> like this on files over 100GB each you can imagine the result.
> 
> 
> 
> As you can imagine even if its a bit silly to write at the same time to the 
> same destination, its also quite common if we want to dump to a log file logs 
> and for some reason one of the writers, write for a lot of time keeping the 
> file locked.
> Our expels are not due to network congestion, but because a write attempts 
> have to wait another one. What i really dont understand is why to take a so 
> expreme mesure to expell jest because a process is waiteing "to too much 
> time".
> 
> 
> I have ticket opened to IBM for this and the issue is under investigation, 
> but no luck so far..
> 
> Regards,
> Salvatore
> 
> 
> 
> On 21/08/14 09:20, Jez Tucker (Chair) wrote:
>> Hi there,
>> 
>>   I've seen the on several 'stock'?  'core'? GPFS system (we need a better 
>> term now GSS is out) and seen ping 'working', but alongside ejections from 
>> the cluster.
>> The GPFS internode 'ping' is somewhat more circumspect than unix ping - and 
>> rightly so.
>> 
>> In my experience this has _always_ been a network issue of one sort of 
>> another.  If the network is experiencing issues, nodes will be ejected.
>> Of course it could be unresponsive mmfsd or high loadavg, but I've seen that 
>> only twice in 10 years over many versions of GPFS.
>> 
>> You need to follow the logs through from each machine in time order to 
>> determine who could not see who and in what order.
>> Your best way forward is to log a SEV2 case with IBM support, directly or 
>> via your OEM and collect and supply a snap and traces as required by support.
>> 
>> Without knowing your full setup, it's hard to help further.
>> 
>> Jez
>> 
>> On 20/08/14 08:57, Salvatore Di Nardo wrote:
>>> Still problems. Here some more detailed examples:
>>> 
>>> EXAMPLE 1:
>>> EBI5-220 ( CLIENT)
>>> Tue Aug 19 11:03:04.980 2014: Timed out waiting for a reply from node 
>>> <GSS02B IP> gss02b
>>> Tue Aug 19 11:03:04.981 2014: Request sent to <GSS02A IP> (gss02a in 
>>> GSS.ebi.ac.uk) to expel <GSS02B IP> (gss02b in GSS.ebi.ac.uk) from cluster 
>>> GSS.ebi.ac.uk
>>> Tue Aug 19 11:03:04.982 2014: This node will be expelled from cluster 
>>> GSS.ebi.ac.uk due to expel msg from <EBI5-220 IP> (ebi5-220)
>>> Tue Aug 19 11:03:09.319 2014: Cluster Manager connection broke. Probing 
>>> cluster GSS.ebi.ac.uk
>>> Tue Aug 19 11:03:10.321 2014: Unable to contact any quorum nodes during 
>>> cluster probe.
>>> Tue Aug 19 11:03:10.322 2014: Lost membership in cluster GSS.ebi.ac.uk. 
>>> Unmounting file systems.
>>> Tue Aug 19 11:03:10 BST 2014: mmcommon preunmount invoked.  File system: 
>>> gpfs1  Reason: SGPanic
>>> Tue Aug 19 11:03:12.066 2014: Connecting to <GSS02A IP> gss02a <c1p687>
>>> Tue Aug 19 11:03:12.070 2014: Connected to <GSS02A IP> gss02a <c1p687>
>>> Tue Aug 19 11:03:17.071 2014: Connecting to <GSS02B IP> gss02b <c1p686>
>>> Tue Aug 19 11:03:17.072 2014: Connecting to <GSS03B IP> gss03b <c1p685>
>>> Tue Aug 19 11:03:17.079 2014: Connecting to <GSS03A IP> gss03a <c1p684>
>>> Tue Aug 19 11:03:17.080 2014: Connecting to <GSS01B IP> gss01b <c1p683>
>>> Tue Aug 19 11:03:17.079 2014: Connecting to <GSS01A IP> gss01a <c1p1>
>>> Tue Aug 19 11:04:23.105 2014: Connected to <GSS02B IP> gss02b <c1p686>
>>> Tue Aug 19 11:04:23.107 2014: Connected to <GSS03B IP> gss03b <c1p685>
>>> Tue Aug 19 11:04:23.112 2014: Connected to <GSS03A IP> gss03a <c1p684>
>>> Tue Aug 19 11:04:23.115 2014: Connected to <GSS01B IP> gss01b <c1p683>
>>> Tue Aug 19 11:04:23.121 2014: Connected to <GSS01A IP> gss01a <c1p1>
>>> Tue Aug 19 11:12:28.992 2014: Node <GSS02A IP> (gss02a in GSS.ebi.ac.uk) is 
>>> now the Group Leader.
>>> 
>>> GSS02B ( NSD SERVER)
>>> ...
>>> Tue Aug 19 11:03:17.070 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:25.016 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:28.080 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:36.019 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:39.083 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:47.023 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:50.088 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:52.218 2014: Killing connection from <EBI5-043 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:03:58.030 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:01.092 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:03.220 2014: Killing connection from <EBI5-043 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:09.034 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:12.096 2014: Killing connection from <EBI5-220 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:14.224 2014: Killing connection from <EBI5-043 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:20.037 2014: Killing connection from <EBI5-102 IP> because 
>>> the group is not ready for it to rejoin, err 46
>>> Tue Aug 19 11:04:23.103 2014: Accepted and connected to <EBI5-220 IP> 
>>> ebi5-220 <c0n618>
>>> ...
>>> 
>>> GSS02a ( NSD SERVER)
>>> Tue Aug 19 11:03:04.980 2014: Expel <GSS02B IP> (gss02b) request from 
>>> <EBI5-220 IP> (ebi5-220 in ebi-cluster.ebi.ac.uk). Expelling: <EBI5-220 IP> 
>>> (ebi5-220 in ebi-cluster.ebi.ac.uk)
>>> Tue Aug 19 11:03:12.069 2014: Accepted and connected to <EBI5-220 IP> 
>>> ebi5-220 <c0n618>
>>> 
>>> 
>>> ===============================================
>>> EXAMPLE 2:
>>> 
>>> EBI5-038
>>> Tue Aug 19 11:32:34.227 2014: Disk lease period expired in cluster 
>>> GSS.ebi.ac.uk. Attempting to reacquire lease.
>>> Tue Aug 19 11:33:34.258 2014: Lease is overdue. Probing cluster 
>>> GSS.ebi.ac.uk
>>> Tue Aug 19 11:35:24.265 2014: Close connection to <GSS02A IP> gss02a <c1n2> 
>>> (Connection reset by peer). Attempting reconnect.
>>> Tue Aug 19 11:35:24.865 2014: Close connection to <EBI5-014 IP> ebi5-014 
>>> <c1n457> (Connection reset by peer). Attempting reconnect.
>>> ...
>>> LOT MORE RESETS BY PEER
>>> ...
>>> Tue Aug 19 11:35:25.096 2014: Close connection to <EBI5-167 IP> ebi5-167 
>>> <c1n155> (Connection reset by peer). Attempting reconnect.
>>> Tue Aug 19 11:35:25.267 2014: Connecting to <GSS02A IP> gss02a <c1n2>
>>> Tue Aug 19 11:35:25.268 2014: Close connection to <GSS02A IP> gss02a <c1n2> 
>>> (Connection failed because destination is still processing previous node 
>>> failure)
>>> Tue Aug 19 11:35:26.267 2014: Retry connection to <GSS02A IP> gss02a <c1n2>
>>> Tue Aug 19 11:35:26.268 2014: Close connection to <GSS02A IP> gss02a <c1n2> 
>>> (Connection failed because destination is still processing previous node 
>>> failure)
>>> Tue Aug 19 11:36:24.276 2014: Unable to contact any quorum nodes during 
>>> cluster probe.
>>> Tue Aug 19 11:36:24.277 2014: Lost membership in cluster GSS.ebi.ac.uk. 
>>> Unmounting file systems.
>>> 
>>> GSS02a
>>> Tue Aug 19 11:35:24.263 2014: Node <EBI5-038 IP> (ebi5-038 in 
>>> ebi-cluster.ebi.ac.uk) is being expelled because of an expired lease. Pings 
>>> sent: 60. Replies received: 60.
>>> 
>>> 
>>> 
>>> In example 1 seems that an NSD was not repliyng to the client, but the 
>>> servers seems working fine.. how can i trace better ( to solve) the 
>>> problem? 
>>> 
>>> In example 2 it seems to me that for some reason the manager are not 
>>> renewing the lease in time. when this happens , its not a single client. 
>>> Loads of them fail to get the lease renewed. Why this is happening? how can 
>>> i trace to the source of the problem?
>>> 
>>> 
>>> 
>>> Thanks in advance for any tips.
>>> 
>>> Regards,
>>> Salvatore
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> gpfsug-discuss mailing list
>>> gpfsug-discuss at gpfsug.org
>>> http://gpfsug.org/mailman/listinfo/gpfsug-discuss
>> 
>> 
>> 
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