10-10-2014 01:53 AM
Hi there,
I have a backup project i am carrying out for our customer. we have had an issue with Cisco MDS FC switch zoned with a tape library and SAN storage.
Every time i run a backup to tape, the FC ports on the tape drive go offline, the FC ports on the switch go offline as well. When i change the cabling on the Cisco switch,the ports on the drive work for a while and then goes offline again.
Please advice if there are any performance configurations to run in the cisco switch since i am backing up TBs of data?
Your help will be appreciated.
regards,
Patrick
10-10-2014 02:22 AM
What is the status of the port in the down state ?
error disable ?
post show port counters
will the port come up again, or do you disable / enable port ?
10-10-2014 04:59 AM
hi wdey,
the ports are showing errDisable, i have disabled and enabled ports and the backup is running..
how do i resolve this permanently?
regards,
Patrick
10-10-2014 05:31 AM
see eg.
http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/69980-errdisable-recovery.html#topic3
Do you see a console / syslog message which should indicate the cause of the errdisable ?
I guess this must be a physical link issue: cable, port, transceiver; do you see crc error counter going up ?
10-14-2014 12:23 AM
Hi wdey,
this is the port status when it goes offline:
SW01# sh int fc1/27
fc1/27 is down (Error disabled - bit error rate too high)
Hardware is Fibre Channel, SFP is short wave laser w/o OFC (SN)
Port WWN is 20:1b:54:7f:ee:e2:8d:00
Admin port mode is auto, trunk mode is on
snmp link state traps are enabled
Port vsan is 2
Receive data field Size is 2112
Beacon is turned off
5 minutes input rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
5 minutes output rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
263045 frames input, 12907156 bytes
0 discards, 0 errors
0 CRC, 0 unknown class
0 too long, 0 too short
4308477 frames output, 8677425352 bytes
1 discards, 0 errors
2 input OLS, 2 LRR, 0 NOS, 3 loop inits
5 output OLS, 2 LRR, 1 NOS, 3 loop inits
Interface last changed at Mon Oct 13 07:36:46 2014
There is this link: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/4_1/configuration/guides/cli_4_1/clibook/intf.html#wp1151733
I referred to the customer to this link on disabling, bit-rate error threshold but the customer is concerned about any disruption on Production Storage (there is a redundant MDS with redundant connectivity to production storage).
does disabling bit-rate affect performance/availability of the switch?
patrick
10-14-2014 12:06 PM
I would investigate what the real problem is; disabling bit-error threshold is bad; in the end, you will have to retransmit the broken FC frames, which will severly impact the performance.
Is this port actually a F-Port ?
switch# show interface
fc1/1 is up
Hardware is Fibre Channel, SFP is short wave laser
Port WWN is 20:0b:00:05:30:00:8d:de
Admin port mode is F
Port mode is F, FCID is 0x610000
Port vsan is 2
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