Things I’ve learned today:
by Jesse on Feb.04, 2008, under Consulting, Fibrechannel, iSCSI
1. iSCSI is a viable alternative to FC for Small infrastructures.
2. I learned that no matter how well prepared for an install you are, the techie-gods will always throw curve-balls at you.
3. I’ve learned that Linux and PowerPath requires that multiple iSCSI HBA’s in a single host are not supported.
(Author’s note – this is not entirely true – see comment #3 below)
4. I’ve learned that seeing mice (yes, plural) running around a datacenter while you’re crawling around on the floor running cables is creepy.
Nuff said. I just got off 20 almost-straight hours in a row (I napped between 3am and 6am this morning) doing what should have been a very very simple install.
Needless to say it wasn’t. I’m going to bed.
-J
February 4th, 2008 on 7:52 am
Doing network work under an airport runway, in a tunnel, I saw a rat as large as a dog. Everyone says I was exaggerating, but damn it was unpleasant!
February 4th, 2008 on 11:13 am
The funniest part was (and I was too exhausted to remember to post this last night) that when I asked them if they’d ever had a problem with mice chewing on cables the response was priceless:
“The mice aren’t that big a deal it’s the raccoons…”
February 7th, 2008 on 11:50 pm
A correction my something i learned…
PowerPath for Linux does in fact support multiple iSCSI HBA’s. However they MUST be in different subnets.
IE
HBA0 – 10.1.1.1/24
HBA1 – 10.1.2.1/24
February 11th, 2008 on 12:11 pm
Cool good stuff to know.. =) My first ISSCI setup was with redhat and just regular nic cards and no special ISCSI tow cards.. Performance was not great or reliable until they did nic port channeling but none the less impressive.
Did you setup security using Chap and all that, or just did security through the zoning and then the masking on the backend storage device?
February 11th, 2008 on 5:18 pm
I’m thinking about playing with that in my VMWare environment, but I don’t have an HA server to put the storage on, so I wouldn’t run anything I depend on on it.
It was pretty straight forward, thank god the customer wasn’t interested in any of the added security, since the storage “SAN” was physically isolated from the user network. So we simply used Masking.
What I found most interesting is that the QLogic 4052 iSCSI HBA stores it’s IP configuration in NVRam. This means that when you have to rebuild a server all of the storage config is already there when you bring it up.
I am curious as to whether anyone has had a specific issue with these HBA’s in a CentOS 5 environment. CentOS5 is binary compatible to RHEL5, but for some reason every time we installed the HBA the kernel would panic very early in the boot cycle. I was thinking that there was bad LVM information on the disk, so deleted and re-created the lun, but no such luck.
iSCSI still involves a lot more voodoo than I like in a production environment.
February 13th, 2008 on 9:01 am
No issues that I’ve seen, had a couple of centos’s…