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Hit Kit vs RHEL Native Multipath
Hello everyone.
I'm new to the forum. We recently setup a RHEL 7.1 server and would like to setup multipath connections to our SAN. What are the pros/cons of using RHEL native multipath vs using the Dell HIT Kit for multipathing?
scottwilsonmusc
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June 7th, 2017 07:00
I would recommend the HIT over normal multipathing.
1. Easier to setup...way easier and it configures all the intricate iscsi settings.
2. If you have a pool of multiple members, it handles the iscsi "slicing/sessions" better than native. We have seen a slight increase in performance (10-15%)
3. Easier to setup mount points and do volume management. The native mapper uses generic names for your volumes mpath0, mpath1, etc..the HIT kit makes "friendly names" that match your volume names. Also if you are doing raw volumes (without a partition), easier to expand online than with normal multipath.
We started on RHEL 5 -> RHEL 7 and when the HIT was finally released for linux, we jumped on it.
Also, if you need host initiated snapshots the HIT kit has the ability to do this with snapshot manager. You cannot do this with native mpio tools.
Scott
chiquita72
2 Posts
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June 7th, 2017 10:00
Thanks for the information Scott. Do you have any experience with expanding lvm when using the HIT Kit? Is it possible to do without having to reformat the filesystem?
scottwilsonmusc
8 Posts
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June 7th, 2017 10:00
We don't use LVM on the SAN. We just use a raw volume and put a file system on it.
mk2fs /dev/eql/
If you expand the volume, you run the rescan-scsi-bus.sh script that RH/CentOS provides and then you can do a
resize2fs /dev/eql/
You can sort of follow the commands from this excellent article I have found.
I love the domain name :-)
www.lazysystemadmin.com/.../resizing-online-multipath-disk-in-linux.html
Anonymous
5 Practitioner
5 Practitioner
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274.2K Posts
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June 7th, 2017 11:00
Hello,
HIT/LE doesn't impact resizing. That's at the disk and filesystem level. HIT/LE manages your iSCSI connections and creates friendly device names.
One thing I always do, is before resizing a volume I create a snapshot on the array. Make sure you have at least 20% reserve. Snapshots don't replace backups but they are great for cases like this. You can roll back in seconds.
Regards,
Don