Slow disk performance using iSCSI on NetWare 6.5

  • 7004527
  • 24-Sep-2009
  • 27-Apr-2012


Novell Open Enterprise Server (NetWare 6.5)
Novell NetWare 6.5 Support Pack 8


Copying files to or from a volume created on an EMC Celerra iSCSI SAN is very slow.  One might also observe a 2-5 minute hang when selecting the 'back' button in Windows Explorer while browsing the volume. 

With the 'SCSIHD.CDM /debug' option applied  the error message '<SCSIHD>GN_CallBack error! Error=80010002.Sense=F000.Ctl=2,Dev=0. MSG=90BD8B80' occurs.

The 'iSCSI Report' output shows the errors:
0x00000018="[!] [CON0:1] watchdog closing socket (25) degraded connection"
0x00000019="[!] HACB Starving wk: [CON0:1] hacb: 994AA560 currentTime: 76B22

A LAN trace shows sense data 1B/4E/00.

It appears that the host makes a request for two different blocks of data in two different packets and the data mover sends the error overlapping commands. Apparently Tag Queuing is not supported in this case.


To fix this issue, execute the following command at the server console (or in an ncf file) before connecting your iSCSI Initiator to the target:

iscsinit reg set Connection Queue Depth=1

You can verify that the 'Connection Queue Depth' is set to 1 by executing the command 'iscsinit reg list'.  This command is persistent across reboots.  This setting causes all iSCSI connections established to send only one command at a time.