ass-u-me: faulty troubleshooting on the NAS

I mentioned earlier that my WD worldbook NAS was apparently dying.  It might be (can’t tell yet), but that wasn’t the real problem.

The symptom was deadly-slow xfer speeds to/from the NAS drive and the USB hd daisy-chained to it.

Testing revealed that:

  • sometimes it worked fine
  • sometimes it worked better from other workstation other than my own
  • but when it fell over it seemed to cause collateral damage;  I attributed this to the cifs/smb network mounted drives becoming practically unavailable.
The real problem revealed itself when I noticed both the his/her Dell antiX laptops were having problems staying on the LAN.  I wan’t used to antiX’s default wicd network tool and assumed it, or my use of it, were faulty.
Googling, googling.  Found a reference to similar symptoms and a fix using ethtool to drop the workstation’s card to 10Mbits/sec rather than some higher number if your router was not playing well.  Tried this and BAM! the connections were rock solid, albeit slow.
My devices were not plugged into a router, but into a switch.  I wonder….
Oh crap.  I went to my non-fixed workstation and looked at dmesg;  eth0 100 was up/down, up/down.  Applied the fix;  instant relief.
So I plopped my backup switch on top and jacked in the cables. All working.
Reset the boxen to their natural speeds; all working.
Did my rsync-based backup routine and speeds are back to reasonable levels for my dinky network:
music/00sorted/pop/Madonna/Immaculate_Collection-ogg/07 - Into_The_Groove.ogg
     3439316 100%    3.19MB/s    0:00:01 (xfer#4582, to-check=25707/42687)
music/00sorted/pop/Madonna/Immaculate_Collection-ogg/08 - Live_To_Tell.ogg
     4363017 100%    3.67MB/s    0:00:01 (xfer#4583, to-check=25706/42687)
So the problem is with the switch.  Dying?  Dunno.  Needs a time out after a few years of constant duty?  Maybe.  I noticed while xferring cables that I had about 5 cables plugged into it that didn’t terminate anywhere.  Dunno if that could cause it confusion.  BTW, my google-fu is failing on researching that possibility,
I learned a great deal fighting this issue, but would have learned faster had I been looking for simpler solutions.  “When you hear hoofbeats, look for horses not for zebras.”  Folksy version of Occam.

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