blog'o thnet - Comments

Getting Emulex HBA Information on a GNU/Linux System - Julien Gabel

Julien Gabel — Fri, 12 Feb 2010 12:38:45 +0100

Well, for scanning new devices on a SCSI chain I just use the script provided by Emulex on their site, and adapt it a little when HBA are from QLogic eventually.

Getting Emulex HBA Information on a GNU/Linux System - Javed Aziz

Javed Aziz — Thu, 04 Feb 2010 10:49:05 +0100

Thanks a lot, i was badly searching HBA commands. If possible plz provide the command for new LUN scanning and initialization.

Stale NFS File Handle - flah

flah — Thu, 07 Jan 2010 22:32:51 +0100

Thanks for the info. Here's a tip:

$ printf "%d\n" 0x1dc24
121892
$ printf "%x\n" 121892
1dc24

Stale NFS File Handle - Julien Gabel

Julien Gabel — Sun, 20 Dec 2009 12:06:32 +0100

Is this to be expected?

Sadly yes, it is a common case, too.

Can I get an other clue of where to look for my inodes?

Well in these cases, I generally tend to use pfiles or dtrace (and eventually lsof), but it is a relatively tedious work... good luck.

Stale NFS File Handle - Marc Girod

Marc Girod — Fri, 18 Dec 2009 17:40:45 +0100

I face a quirk: my file systems are automounted.
The device id I get seems constant, but doesn't match anything in /etc/mnttab: 62000000.

Is this to be expected? Can I get an other clue of where to look for my inodes?

Stale NFS File Handle - Marc Girod

Marc Girod — Thu, 17 Dec 2009 13:13:55 +0100

> there's no way to terminate the find upon finding the file

I am not sure about Solaris tools, but GNU head will close its stdin after completion, which will result in a SIGPIPE, which kills the GNU find.
So, the following idiom should do the trick:

find ... | head -1

Thanks for all this useful info.

Stale NFS File Handle - unknown

unknown — Tue, 01 Dec 2009 15:16:03 +0100

#!/bin/sh
#
# fhfind: takes the expanded filehandle string from an
# NFS write error or stale filehandle message and maps
# it to a pathname on the server.
#
# The device id in the filehandle is used to locate the
# filesystem mountpoint. This is then used as the starting
# point for a find for the file with the inode number
# extracted from the filehandle.
#
# If the filesystem is big - the find can take a long time.
# Since there's no way to terminate the find upon finding
# the file, you might need to kill fhfind after it prints
# the path.
#

if [ $# -ne 8 ]; then
echo
echo "Usage: fhfind <filehandle> e.g."
echo
echo " nfsfind 1540002 2 a0000 4df07 48df4455 a0000 2 25d1121d"
exit 1
fi

# Filesystem ID

FSID1=$1
FSID2=$2

# FID for the file

FFID1=$3
FFID2=`echo $4 | tr [a-z] [A-Z]` # uppercase for bc
FFID3=$5

# FID for the export point (not used)

EFID1=$6
EFID2=$7
EFID3=$8

# Use the device id to find the /etc/mnttab
# entry and thus the mountpoint for the filesystem.

E=`grep $FSID1 /etc/mnttab`
if [ "$E" = "" ]; then
echo
echo "Cannot find filesystem for devid $FSID1"
exit 0
fi

set - $E
MNTPNT=$2

INUM=`echo "ibase=16; $FFID2" | bc` # hex to decimal for find

echo
echo "Now searching $MNTPNT for inode number $INUM"
echo

find $MNTPNT -mount -inum $INUM -print 2>/dev/null

Finding The Process Responsible For Crashing A System - Karl Arao

Karl Arao — Mon, 26 Oct 2009 05:46:07 +0100

Nice troubleshooting :)

Comparison: EMC PowerPath vs. GNU/Linux dm-multipath - Julien Gabel

Julien Gabel — Sat, 19 Sep 2009 16:32:57 +0200

It is not easy to answer concisely to these questions, however here are some inputs:

How difficult is it to force the re-installation of the software?

When you know it, it not as difficult. It is just not convenient, at 3am not to see your more than 7TB database not came up again after an OS upgrade because under GNU/Linux the modules are installed in a path which include the exact number and revision of the installed and running kernel. At last, it is not particularly elegant, and it must exists a better way.

What effects on the configuration of the running system will this have - Would a reboot be required? (Surely a kernel upgrade would require this any way?!)

The upgrade must be done using a running system. So, you have to quiesce your activity during this time, and reboot quickly after that. This must be part of a planned intervention window nevertheless. So, you must have to reboot in single-user, force a re-installation of the PowerPath RPM package (and have it available in single-user mode), then reboot in multi-user mode.

I'm from a Solaris background & am new to the Linux world: How often do you upgrade your kernel on a critical production system used as an Oracle dB server that almost never changes other than have more LUNs or HBAs added? Is this kernel update something you perform weekly, or per annum?

As you may know (if you read my blog), I am more well versed in Solaris too. The fact is, when you upgrade regularly for integrity, bug and security fixes, the kernel is sometimes impacted. When using Linux, the major revision of the kernel is the same, just the minor number is updated, but this is the base of the problem I described earlier. On Solaris, even if the kernel is impacted, the changing number for the generic kernel is never a problem for this type of intervention.

Depending on the number of times you have to upgrade, my point is you never have to encounter the problem I faced with Linux.

Comparison: EMC PowerPath vs. GNU/Linux dm-multipath - serfKong

serfKong — Fri, 11 Sep 2009 12:56:37 +0200

I don't quite follow the probable impact of this on a system: 'The need to force a RPM re-installation in case of a kernel upgrade on RHEL systems (due to the fact that kernel modules are stored in a path containing the exact major and minor versions of the installed (booted) kernel.'

1) How difficult is it to force the re-installation of the software?

2) What effects on the configuration of the running system will this have - Would a reboot be required? (Surely a kernel upgrade would require this any way?!)

3) I'm from a Solaris background & am new to the Linux world: How often do you upgrade your kernel on a critical production system used as an Oracle dB server that almost never changes other than have more LUNs or HBAs added? Is this kernel update something you perform weekly, or per annum?

Best regards.

Complete Step-by-Step Guide to Create, Install and Configure a Fully Fonctional DLPAR - Raul

Raul — Tue, 28 Jul 2009 22:27:05 +0200

simply PERFECTLY EXPLAINED.... never seen more clean , professional and clearly explanation of how to do this job.
Thanks. BTW: I am kind of Jr.or Ssr. SA working for EDS. cheers

GRUB Boot Archive With SVM, A Better Approach - dieter

dieter — Tue, 07 Jul 2009 22:48:42 +0200

Dude,

You just saved me a night's work with this :)
Thanks for the clear explanation!

Dieter.

Discrepancies Between df And du Outputs - karthik

karthik — Tue, 09 Jun 2009 20:28:29 +0200

Excellent work around.

Comparison: EMC PowerPath vs. GNU/Linux dm-multipath - Julien Gabel

Julien Gabel — Sun, 10 May 2009 19:58:23 +0200

Well, no it is not a joke... per-se :)

The fact is, I try to give both for and against multipath inputs. I think the two first points are valid. It doesn't mean they are for you, even if the very first point is just a fact.

As for the third point, I didn't encounter this kind of configuration file with other multipath and LVM technologies.

Comparison: EMC PowerPath vs. GNU/Linux dm-multipath - Rui Seabra

Rui Seabra — Sat, 09 May 2009 18:23:05 +0200

Ha! Your list of drawbacks for the multipath version is a joke, right? :)

1. not a problem
2. not a problem
3. since LVM is really adviseable, not a problem as well.

Thank you very much for your comparison, it will really help me when the HBA cards for a couple of systems do arrive.

ZFS on a USB Disk (removable Media) - Alexandre Dumont

Alexandre Dumont — Sat, 09 May 2009 00:20:44 +0200

You might be interested in ZFS Automatic Backup to USB disks: http://blogs.sun.com/timf/entry/zfs...

Problem Querying ru. Name Servers - Kolo

Kolo — Tue, 05 May 2009 19:09:05 +0200

Different PTR record is not a problem at all. There is no rule / recommendation that NS names must match PTR record. Both ns3.nic.ru and ns3.ripn.net are correct.

Problem is with RU-CENTER (nic.ru) DNS'es itself.

Upcoming IBM AIX 6 features vs. Sun Solaris 10 and OpenSolaris - Octave Orgeron

Octave Orgeron — Mon, 13 Apr 2009 05:33:55 +0200

Actually, while the SPARC64 processors are based on technology from Fujitsu, they share the development of those processors. The recent SPARC64 VII processors actually made use of some know-how from Sun and not Fujitsu. The CMT processors (UltraSPARC-T1/T2/T2+) are Sun designs and outsell the M-series servers hands down. Not to mention that many benchmarks have shown the UltraSPARC-T2 and T2+ systems to outperform Power6 systems on price and performance.

ZFS on a USB Disk (removable Media) - Julien Gabel

Julien Gabel — Sun, 15 Mar 2009 19:49:22 +0100

The fact is, both pools will have a snapshot copy of the original file system after the send/recv. So, both can be deleted. In my example, I decided to delete the target snapshot, which explain why the zfs list didn't display it.

ZFS on a USB Disk (removable Media) - cmeiring

cmeiring — Sun, 15 Mar 2009 12:44:38 +0100

zfs destroy rmzp/home/jgabel@rmzp.0 ?

reading as a old school admin it should be datazp, but maybe the receive command works different than my first idea, just starting with zfs.