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WinkyWolly
Asked: 2013-05-24 11:02:38 +0800 CST

Installing RHEL on a single disk with ZFS

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I know ZFS is usually used for numerous reasons including it's amazing mirroring features. However in this instance the machine I've been tasked with setting up has a RAID-1 setup so I only have one logical disk.

My reason for wanting ZFS is primarily that of snapshots - is this the right tool for the job or is there a better way to efficiently emulate ZFS snapshot?

I'm having a chicken or egg problem - is it possible to install a base RHEL system with one disk (/dev/sda) using ZFS? It seems all references I can find use it to pool numerous disks with the base system not being mentioned. How would I achieve this?

Please let me know if I can clarify this at all as I'm fully aware my explanation is lackluster at best.

linux

1 Answers

  1. I'll answer. You may be overthinking...

    Snapshots aren't backups. So if you're trying to protect against a compromise, you should go the extra step and back up to another device. Now, snapshots can be extremely helpful in producing a clean consistent copy of your data to ship or back up to another device.

    As far as ZFS on Linux, It's very easy to integrate into existing RHEL installs. I only use ZFS on data partitions, though. If I have a Linux system, I boot using the normal default filesystems. In the example below, on the /data partition is a ZFS filesystem. That way, I can snapshot or apply granular settings (compression in this case) where they're needed.

    [root@MDMarra ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/cciss/c0d0p2      12G  2.4G  8.9G  22% /
tmpfs                 7.8G  4.0K  7.8G   1% /dev/shm
/dev/cciss/c0d0p1     291M   59M  218M  22% /boot
/dev/cciss/c0d0p7     2.0G  119M  1.8G   7% /tmp
/dev/cciss/c0d0p3     9.9G  1.9G  7.5G  21% /usr
/dev/cciss/c0d0p6     6.0G  318M  5.3G   6% /var
vol1/data             118G   55G   63G  47% /data

    If you just need the ability to create a block device snapshot at any time, Idera Hot Copy can do the job. These snapshots won't persist across reboots, though.

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