Fibre Channel (SAN)

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New Contributor
Posts: 3
Registered: ‎01-12-2005

Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

I have recently installed two new Brocade 48000 directors running 5.1.0d and upgraded part of our 3584 tape library to add new 4Gb LTO Gen 3 tape drives. I am constantly having these 4Gb drive ports report INW and CRC errors. The ports go marginal and then healthy and then marginal again. Installed all new 50mu fibre cables for these drives and the other 2Gb LTO Gen 3 drives. Only the 4Gb drives are giving the errors. Are these new drives just more sensitive and I need to adjust switch port error thresholds? Or could there be a firmware issue? My Operations team says everything is running better than ever, and don't want me to change anything. These errors must be slowing backups down, but the increase in performance must be offsetting the errors, which I assume cause data to be retransmitted. Any ideas?

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

hi, i am not sure but i think this as incompatibility problem whit the Port / SFP from switch to LTO Drive. please check is the port correct configured, see here the current loaded firmware resease notes from LTO and the Brocade Compatibility Matrix.

TechHelp24
Occasional Contributor
Posts: 13
Registered: ‎03-01-2007

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

Hello,

I just read your post and it sounds just like errors I'm receiving when connecting my 48000 to a 5100 via longwave fibre ISL.  How were you able to solve your problem??

Thank you!

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

pls do a portstatsclear on those ports and see the errors' value is  increasing thorugh portstatsshow . check thorugh porterrshow also.for marginal ports check switchstatusshow, errdump

you can try to reset the drives also from TL side.

you have changed the cables, now you have to try by changing the SFP.

Gen 3 drives sometimes behave liek this.So you may have to reset the drives, But first you do all the possible changes from SAN side and check the compatibility matrix.

Fro this trouble shooting you have to look from a broader angle and to do a lots of changes one by one.

Occasional Contributor
Posts: 13
Registered: ‎03-01-2007

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

Thank you for your reply.  Actually, we ended up forcing the 5100's ISL port to run at 2GB/s speed and the ISL worked fine!  Previously, the ISL was connected to a 2GB/s McData Director and we moved it to the 5100, which has 4GB/s SFP's.  It seems our patch panel is not equipped to handle 4GB/s speed (my guess), because setting the ISL port  to 2GB/s fixed the problem.

Thanks again!

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

This is nothing to do with patch panel.

Initially u have mentioned about 48K Dirs, then how come 5100 came in to the scenario?

Could you pls explain elaborately.

Occasional Contributor
Posts: 13
Registered: ‎03-01-2007

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

I didn't start the post--I replied to the person who started the post.  That person was having INW errors on his 48000.  In my post, I mention that I have a 48000 ISL'd to a 5100, which was getting a lot of INW errors.

My 5100 has 4GB/s longwave SFP's, so what else could it be, other than the patch panel?

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Getting a lot of INW & CRC errors on new 48000 with 4GB LTO gen 3 drives

oh , sorry, I mistaken ur answer.

Anyway 48K LWL sfp must be 4 gbps and 5100 LWL SFP is 4 Gbps ,as  you said, then it should auto negotiate to 4 Gbps.and regarding fibre cable it must be SMF.Then forcing into 2 Gbps , strange..

btw thank you for sharing ur practical experience to the forum..

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