[Info-vax] Sudden problems with slow sftp transfers and slow disk accesses

[Jan-Erik Soderholm]

Jim wrote 2014-02-18 12:23:
> On Monday, February 17, 2014 11:42:27 PM UTC-5, gwil... at cfa.harvard.edu wrote:
>> Cluster of 8 Alpha boxes running V8.3 + patches, recently moved
>>
>> from one building to another.  Since the move, we've been experiencing
>>
>> odd behaviors: very slow network access (via sftp) and slow disk IO.
>>
>>
>>
>> Disk storage is mostly on three eternal disk boxes (five three-member
>>
>> shadow sets).  No errors are reported via SHOW DEV DSA.
>>
>>
>>
>> Network cards on all machines are set to 100 MB, full duplex,
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>> non-autonegotiate, connected via an 8-port GB switch.
>>
>>
>>
>> An sftp from one of our machine to a local Linux system transferred 288 KB
>>
>> of a ~ 6MB file in the first second, the current rate is now down to 5KB/s.
>>
>> MONITOR PROCESS/TOPCPU doesn't show the process getting even 1% of the
>>
>> CPU and there is nothing else running on the system.  Another attempt on
>>
>> the same file transferred 1.5 MB in the first second, then dropped to
>>
>> < 50 KB/s.
>>
>>
>>
>> SHOW MEMORY doesn't show any problems.
>>
>>
>>
>> A filing operation merging two large files took a matter of seconds
>>
>> when both files were on a locally-attached disk.  When both files were
>>
>> on a shadow set, the merge took 6+ minutes.  MONITOR LOCK while
>>
>> running the latter test showed ENQ/DEQ rates < 1.
>>
>>
>>
>> Image activation is slow.  It can take several seconds to begin
>>
>> running an .exe stored on the shadow set.
>>
>>
>>
>> MCR SCACP SHOW LAN_DEV/ALL showed numerous errors occurring over the
>>
>> past 24 hours, so this evening we replaced the switch connecting these
>>
>> 8 machines.  Errors are continuing to appear.
>>
>>
>>
>> What am I missing?
>>
>>
>>
>> Gareth
>
> The output of the following command might be interesting
>
> $ MCR LANCP SHOW DEVICE/INTERNAL Exxx ! where Exxx is the suspect NIC
>

*I* would focus on what has actualy *changed*.

The Alphas are the same, just moved, so I would not look there.

The environment (comp.room, switches and so on) are new, so
I would first look *there*.

Regards,
Jan-Erik.