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LUN presentation

Occasional Contributor

LUN presentation

I have present a 100GB to my redhat blade serrver.
can Any one help me with the steps I have to take to make is availble as a mount point during booting for users.I dont have any multipath.
Michal Kapalka (mikap)
Honored Contributor

Re: LUN presentation


you can use a native multipath from redhat.

Honored Contributor

Re: LUN presentation

First, what's the technology you're using to present the LUN?

When someone talks about "presenting a LUN", the technology is usually either FibreChannel or iSCSI, but it might be something else too.
Each technology can have somewhat different procedures.

After the LUN is made visible to the OS, the rest of the procedure is pretty much common to most storage technologies. But you must make some decisions first:

* Do you wish to create a PC-style partition table or not?

+ in a mixed Linux/Windows environment, a PC-style partition table makes it easier to notice that a LUN is already in use, in case the SAN administrator makes a mistake

- creating the partition table requires extra work and wastes a small portion of disk space

(-) a PC-style partition table cannot be used if the LUN size is over 2 TB. But that's not a problem here.

* Do you wish to use LVM or not?

+++ LVM makes it very easy to expand the filesystem to other LUNs while it's mounted, if you need extra capacity later

- Of course, you must understand LVM to use it effectively. But it is not very difficult.

If you use LVM, you may either create a new volume group or extend an existing one. Then you must create a new Logical Volume using the volume group of your choice.

If you choose to not partition the LUN, you should at least use LVM with it. Although creating a filesystem on the unpartitioned whole-LUN device is possible, it's usually a bad idea.

* Which filesystem type you wish to use?

The default choice on RedHat Linux is ext3, but depending on your requirements, you might wish to use some other filesystem type, like ReiserFS or XFS.

* And finally, where should the mount point be located?

Steven E. Protter
Exalted Contributor

Re: LUN presentation


Red Hat back to version 4 has multipath built in. If there are two paths to the same disk, they will show up and need to be accounted for.

fdisk -l

Please post

Steven E Protter
Owner of ISN Corporation
Occasional Advisor

Re: LUN presentation

Do you mean scanning the scsi bus to add the LUN to the server? Or formatting a file system on the LUN?

Also, what kernel version is the server running?