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

[Jim]

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