So I ran into this odd issue last night working in the old homelab. I was working on troubleshooting an issue with datastore performance on one of my Supermicro ESXi servers. I have two and they are awesome beasts that have been migrated into fancy Cooler Master cases, however that is a tale for another day. Anyway, I digress… the datastore. So yeah, it's a local raid 5 datastore attached to an LSI 9260-8i controller. This particular datastore is 3 600gb 15k SAS drives, and for some reason its slow as all get-out.
So being the command line guy that I am, I ssh from my Linux (Fedora 19, specifically) into my troublesome ESXi server and attempt to run esxtop to see if I can get a read on the disks. Much to my chagrin, the output of esxtop is a garble of text Unreadable to say the least.
Turns out that this is an issue related to terminal emulation type. Thanks to this bro, who ran into same issue on his Mac, I was able to get back in the game and determine that yes, you should not configure raid 5 with a dead BBU. Anyway, while his fix was not exactly help for me, it let me know what I needed to do to fix this issue.
The gist of the issue is this. In Linux (Fedora at the very least) the default terminal emulation type is xterm-256color. Set your terminal type to this, ssh to and ESXi 5.5 box, and experience this formatting debacle for your self.
Thankfully the fix is simple, just change your terminal emulation type to "xterm" and you will be good to go. I accomplished this with the command below.
# export TERM=xterm
I can tell you this, I never had issues ssh'ing to ESXi 5.0 from Linux, so this was probably introduced in ESXi 5.5