The inevitable TAC call and the request for a Show Tech to help with the support. Normally this is not a big problem on most systems, but if you ever try this on somehting like a Nexus 7000 – it takes a loooooong time and pulls well over 100 megs of information in that file. Capturing this output to a terminal is a test of patience (lets not mention console), or even if you redirect it to the bootflash it can still take some time. Then, there is getting a 100+ meg file copied from the bootflash to your computer, etc etc etc. I did do a quick post some time ago about using GZip to compress the file – you can find that post here.
But that is not what this post is about, this post is about a command called TAC-PAC. TAC-PAC seems to be a little known command to most people who have never run into a problem and had to pull a show tech of a N7K, of for that matter any NX-OS platform. I was able to confirm this command on Nexus 7000, 5000, and 1000 as well as the SAN MDS.
So, what is TAC-PAC? It is a single command that redirects the output of show tech-support details to a file, and then automatically compresses it for you. One command – nice and simple. The only thing that you will still have to do is pull the file via FTP or so.

So, how does one use TAC-PAC? Well, here are the commands and such:
Lets first see what the systems tells us about TAC-PAC:
NXOS# tac-pac?
tac-pac Save tac info in a compressed .gz file at specific location

Now lets find out what options we have for the TAC-PAC
NXOS# tac-pac ?
<CR>
bootflash: Select destination filesystem
ftp: Select destination filesystem
logflash: Select destination filesystem
scp: Select destination filesystem
sftp: Select destination filesystem
slot0: Select destination filesystem
tftp: Select destination filesystem
volatile: Select destination filesystem

Ok, I see we can save it multiple locations – but for me I prefer to save it locally and then pull it back from there. Why? Well, if you rely on any of the remote copy commands and you lose your connection, you might be running this command again. Easier to save it locally then pull it from there in my opinion.
So, lets save it to the bootflash. When we ran it, we did have some notices come back – they are listed as they appeared.
NXOS# tac-pac bootflash:
No kernel traces found
No kernel traces found
NXOS#
Ok, now that it is done lets take a look at the bootflash:
NXOS# dir bootflash:
14029324 Apr 18 01:26:53 2012 show_tech_out.gz
Usage for bootflash://sup-local
818855936 bytes used
991043584 bytes free
1809899520 bytes total
NXOS#
There we go, we have a show_tech_out.gz file ready to copy to your computer and send to TAC. Oh btw, it did not take that long to run – I did not time it, but it was quicker then I expected. When we look at that compressed 14 meg GZ file, there is a 200 meg file there waiting to be viewed!
Last thing, what does this run? Over 3000 show commands, way too many for me to list here!