Hello All,
I want to extend my diskspace with a RAID5 (external). Preferably with ESATA connection to my B3.
Has anyone experience with this and a type that is not to expensive to use?
Rene
Please note the new address for this forum : forum.excito.org. The old address redirects here but I don't know for how long. Thanks !
New user's registration have been closed due to high spamming and low trafic on this forum. Please contact forum admins directly if you need an account. Thanks !
RAID5
Re: RAID5
Since the B3 only has one eSata port and you need at least three disks for a RAID 5 setup you need an external box with four disks (they usually come in 2, 4 and 8 disks). One of the things to look out for is that you need one with a port multiplier, a FIS based one. Excito has tested one and couldn't get it to work, but the B3 is able to use a port multiplier. Best thing is to ask the shop you buy it from if you can return it.
Usually these boxes have an USB 2 and one eSata port, and you can switch it (on the box) from JBOD (separate disks) to RAID 1 and RAID 5. If you set it to RAID 5 then you don't have to do more than plug it in, the box will do the RAID stuff. If you want the B3 to do that then you have to set it to JBOD (Just a Bunch Of Disks).
Depending if you have your B3 set up to mirror the /home directory (which can be done by using on of the four external disks for mirroring the internal disk, the three others for RAID 5) you have one or two raid devices /dev/md0 and /dev/md1.
Assuming you haven't done this mirroring you will have to create a raid set /dev/md0.
If your extra disks (in the external box) are recognised as /dev/sdb, /dev/sdc, /dev/sdd, /dev/sde you have to create the raid set:
mdadm --create /dev/md0 --level 5 --raid-devices 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
(this will take some time, check the progress with cat /proc/mdstat)
add it to /etc/mdadm/mdadm.conf to make it permanent:
mdadm --examine --scan >> /etc/mdadm.conf
Now you can create a file system on it:
mkfs -t ext3 /dev/md0
create a mount point:
mkdir /raid5
and add the following line to fstab:
/dev/md0 /raid5 auto defaults 0 2
now you can simply mount it:
mount /raid5
and he presto, there is your raid 5 set.
External disk boxes with port multiplier can be found e.g. from brands like fantec, icybox, etc.
They will cost from 100 Euro upwards, excluding the disks.
But as of today no report have been made of succesfully using an external box with port multiplier.
Hope this gives you some ideas how to continue.
Good luck and keep us informed on your progress.
Albert
Usually these boxes have an USB 2 and one eSata port, and you can switch it (on the box) from JBOD (separate disks) to RAID 1 and RAID 5. If you set it to RAID 5 then you don't have to do more than plug it in, the box will do the RAID stuff. If you want the B3 to do that then you have to set it to JBOD (Just a Bunch Of Disks).
Depending if you have your B3 set up to mirror the /home directory (which can be done by using on of the four external disks for mirroring the internal disk, the three others for RAID 5) you have one or two raid devices /dev/md0 and /dev/md1.
Assuming you haven't done this mirroring you will have to create a raid set /dev/md0.
If your extra disks (in the external box) are recognised as /dev/sdb, /dev/sdc, /dev/sdd, /dev/sde you have to create the raid set:
mdadm --create /dev/md0 --level 5 --raid-devices 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
(this will take some time, check the progress with cat /proc/mdstat)
add it to /etc/mdadm/mdadm.conf to make it permanent:
mdadm --examine --scan >> /etc/mdadm.conf
Now you can create a file system on it:
mkfs -t ext3 /dev/md0
create a mount point:
mkdir /raid5
and add the following line to fstab:
/dev/md0 /raid5 auto defaults 0 2
now you can simply mount it:
mount /raid5
and he presto, there is your raid 5 set.
External disk boxes with port multiplier can be found e.g. from brands like fantec, icybox, etc.
They will cost from 100 Euro upwards, excluding the disks.
But as of today no report have been made of succesfully using an external box with port multiplier.
Hope this gives you some ideas how to continue.
Good luck and keep us informed on your progress.
Albert
Re: RAID5
Made a small typo:
mdadm --create /dev/md0 --level 5 --raid-devices 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
Should be:
mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
the equal sign is necessary when using the full description commands, in short this should be:
mdadm -C /dev/md0 -l 5 -n 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
Albert
mdadm --create /dev/md0 --level 5 --raid-devices 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
Should be:
mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
the equal sign is necessary when using the full description commands, in short this should be:
mdadm -C /dev/md0 -l 5 -n 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
Albert