alfonso78
October 16th, 2011, 12:02 AM
Hi,
I created a RAID6 out of 4 disks of 2TB each, so I have 4TB of space and 4TB of redundancy. This way I can withstand two disks failures.
Off-topic, but if you're going for RAID6, have a look at these two articles, they are quite interesting:
http://www.techrepublic.com/blog/datacenter/raid-6-do-you-really-want-it/119
http://www.zdnet.com/blog/storage/why-raid-6-stops-working-in-2019/805
I created the RAID array using mdadm commands (there are several howtos, you can try this one for example: http://web.archive.org/web/20091122090221/http://raid.wiki.kernel.org/index.php/RAID_setup )
then I created a partition over /dev/md0
(1st I tried with fdisk without realizing the partition would be only 2TB, so I had to recreate the partition with parted - see http://ubuntuforums.org/showpost.php?p=11349393&postcount=1 )
On top of the partition /dev/md0p1 I created a filesystem and then following this howto I created the encrypted partition on top of /dev/md0p1:
http://www.hermann-uwe.de/blog/howto-disk-encryption-with-dm-crypt-luks-and-debian
And then an ext4 partition in the encrypted volume (why ext4? no idea. at first I wanted to use JFS, then I couldn't find some commands and decided for ext4).
for additional info, this is only the data partition, so no need to boot from it.
Finally my question:
do I need an extra layer of LVM before the encryption or after the encryption? From what I understand, LVM is only useful if I want to have multiple partitions, but I don't think I need that.
Right now I'm not using LVM at all.
According to howtos, I can simply grow my RAID array changing each disk with a bigger one (see http://h3x.no/2010/03/02/howto-increase-disk-space-in-a-mdadm-raid or http://blogging.dragon.org.uk/index.php/mini-howtos/howto-use-linux-raid-5 )
and I can grow both the LUKS encrypted device (see http://www.debian-administration.org/article/Resizing_Encrypted_Filesystems ) and the ext4 filesystem inside it ( see http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/ext4grow.html ).
So what is the advantage of LVM? Do I need it?
From this post I get an idea: https://bbs.archlinux.org/viewtopic.php?id=126502
The guy says he wants to have only one password. Is this one possible reason?
I created a RAID6 out of 4 disks of 2TB each, so I have 4TB of space and 4TB of redundancy. This way I can withstand two disks failures.
Off-topic, but if you're going for RAID6, have a look at these two articles, they are quite interesting:
http://www.techrepublic.com/blog/datacenter/raid-6-do-you-really-want-it/119
http://www.zdnet.com/blog/storage/why-raid-6-stops-working-in-2019/805
I created the RAID array using mdadm commands (there are several howtos, you can try this one for example: http://web.archive.org/web/20091122090221/http://raid.wiki.kernel.org/index.php/RAID_setup )
then I created a partition over /dev/md0
(1st I tried with fdisk without realizing the partition would be only 2TB, so I had to recreate the partition with parted - see http://ubuntuforums.org/showpost.php?p=11349393&postcount=1 )
On top of the partition /dev/md0p1 I created a filesystem and then following this howto I created the encrypted partition on top of /dev/md0p1:
http://www.hermann-uwe.de/blog/howto-disk-encryption-with-dm-crypt-luks-and-debian
And then an ext4 partition in the encrypted volume (why ext4? no idea. at first I wanted to use JFS, then I couldn't find some commands and decided for ext4).
for additional info, this is only the data partition, so no need to boot from it.
Finally my question:
do I need an extra layer of LVM before the encryption or after the encryption? From what I understand, LVM is only useful if I want to have multiple partitions, but I don't think I need that.
Right now I'm not using LVM at all.
According to howtos, I can simply grow my RAID array changing each disk with a bigger one (see http://h3x.no/2010/03/02/howto-increase-disk-space-in-a-mdadm-raid or http://blogging.dragon.org.uk/index.php/mini-howtos/howto-use-linux-raid-5 )
and I can grow both the LUKS encrypted device (see http://www.debian-administration.org/article/Resizing_Encrypted_Filesystems ) and the ext4 filesystem inside it ( see http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/ext4grow.html ).
So what is the advantage of LVM? Do I need it?
From this post I get an idea: https://bbs.archlinux.org/viewtopic.php?id=126502
The guy says he wants to have only one password. Is this one possible reason?