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How to get ALL then FC info you need (and more!)

Here's the cheet sheet to using native FC tools and drivers (tested on rhel5):

pWWN = cat /sys/class/fc_host/host[0-9]/port_name
WWN = cat /sys/class/fc_host/host[0-9]/node_name
online? = cat /sys/class/fc_host/host[0-9]/port_state
Speed = cat /sys/class/fc_host/host[0-9]/speed
HBA overview = cat /sys/class/fc_host/host[0-9]/symbolic_name
/sys/class/fc_host/host[0-9]/device/scsi_host\:host[0-9] is same as /sys/class/scsi_host/host[0-9]
HBA make = cat /sys/class/scsi_host/host[0-9]/model_desc
HBA model = cat /sys/class/scsi_host/host[0-9]/model_name
Firmware rev = cat /sys/class/scsi_host/host[0-9]/fw_version
Driver version = cat /sys/class/scsi_host/host[0-9]/driver_version
rescan scsi bus (use VERY wisely) = echo "- - -" > /sys/class/scsi_host/host[0-9]/scan
issue lip (use even MORE wisely) = echo 1 > /sys/class/fc_host/host[0-9]/issue_lip

It's a good cheet sheet, but you'll need more understanding to make this useful for your troubleshooting. Read on.

How to Get VMware Cluster To Use Different CPU Types

In case you didn't think it through (like I didn't), you can't vMotion guests from one type of CPU to another. And when I say type, I don't just mean AMD to Intel, I mean different models and generations. For example, you can't go from Family 6, Model 46 (2Eh) = Nehalem-EX to Family 6, Model 47 (2Fh) = Westmere-EX/E7... at least not live. It makes sense. However, there is one exception: EVC.

How do you scan for new luns on linux?

I always forget this one. How exactly do you find those new fibre channel luns you carved and presented to the host? The zoning is there, but you need to have the OS look for it.

Well, if you have power path or other vendor software it will be different and I'll document that as well some day. Using the native software in RHEL 5.1 or greater, you do this.

Power Notes

I am have spent a LOT of time in data centers, but that doesn't mean I always remember all the details.

Recepticle types:
L5-20 = power outlet you have at home {add pictures}. 120V with up to 20A draw (16A safe {80%})
L6-20 = 208V, 20A
L6-30 = 208V, 30A
Add in the exadata fiasco here (60A!!)

KVA v. Watts
Bascially, Watts is a meausre of max power, KVA is complicated, but is a better number as it accounts for resistance, heat and other imprefections of this imperfect world.

Notes on RHEL Server as a desktop

I've been using RHEL5 as my desktop since 9/2009. I thought it was best to work on the same OS as the servers. Ultimately, I think that was a bad idea and I will be switching to Fedora soon. Here's my notes to remind me how to do things I rarely do.

growisofs -dvd-compat -Z /dev/dvd=RHEL6.0-20100715.2-Server-i386-DVD1.iso

How to add storage to oracle blade servers via qlogic and powerpath

I inherited a rhel4, 10g rac with EMC Clariion storage. Here's how I add more storage to keep it on life support.

Can't Login to Exadata

I've had this come up a few times. Exadata is configured to require big passwords, that expire AND will lock you out after 5 failed login attempts... which happen often after password changes. What's an admin to do?

Check the logs:

/usr/bin/faillog

And the output looks something like:

Login Failures Maximum Latest On
root 0 0 01/01/70 00:00:00 +0000
...
grid 0 0 01/01/70 00:00:00 +0000
oracle 0 0 01/01/70 00:00:00 +0000

Huh? I guess we're not using faillog anymore ... it's time for pam_tally2

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