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We have random backup failures in master drive0

maria_jose_carr
Level 1
Hello, We have two HP libraries (MSL2024 and MSL8096). We have random backup failures and the drives change to AVR status. We've checked: - Update the firmware HP. - Check the FC. - Check switch log (only view this error): c3-timeout tx: The number of transmit class 3 frames discarded at the transmission port due to timeout (platform- and port-specific). This indicates an issue with the device connected to the switch. - HP support confirm the hardware is correct. - Check zonning. If we stop drive 0 (master drive) from netbackup there are no errors backups. Any idea it might be the cause? Thanks in advanced
1 ACCEPTED SOLUTION

Accepted Solutions

Nicolai
Moderator
Moderator
Partner    VIP   

SAN troubleshooting is a bit out of this forums comfort zone. 

if you have C3 discards, it's bad. I recommend requesting help from a experienced SAN admin to troubleshoot the issue. You can have perfectly working hardware and C3 discards at the same time. A C3 discard is basically a frame that get thrown away during transmission, and since Fibre Channel is designed as a lossless protocol this is bad.Likely you are looking into more than just one error to eliminate the C3 discards. Many small streams make big river

Small Advice from me:

Make sure all devices are at the same speed (2,4,8,16,32GB)
Zone one hba to one tape drive, do not zone one HBA to all tape drives in one zone.
One HBA to 1-2 tape drives at the most, tape drives are fast than you think when applying build-in compression.

Best Regards
Nicolai

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1 REPLY 1

Nicolai
Moderator
Moderator
Partner    VIP   

SAN troubleshooting is a bit out of this forums comfort zone. 

if you have C3 discards, it's bad. I recommend requesting help from a experienced SAN admin to troubleshoot the issue. You can have perfectly working hardware and C3 discards at the same time. A C3 discard is basically a frame that get thrown away during transmission, and since Fibre Channel is designed as a lossless protocol this is bad.Likely you are looking into more than just one error to eliminate the C3 discards. Many small streams make big river

Small Advice from me:

Make sure all devices are at the same speed (2,4,8,16,32GB)
Zone one hba to one tape drive, do not zone one HBA to all tape drives in one zone.
One HBA to 1-2 tape drives at the most, tape drives are fast than you think when applying build-in compression.

Best Regards
Nicolai