Hardware Raid + hot-replace failed disk
Pieter.Donche at ua.ac.be
Fri Nov 7 01:35:42 PST 2008
On Thu, 6 Nov 2008, Wojciech Puchar wrote:
>> Suppose you have a system with multiple disks managed by a
>> hardware RAID controller in a RAID5 of RAID6 configuration,
>> To FreeBSD it will look like e.g. a single large drive.
> what is "RAID5 of RAID6"???
RAID5 or RAID6 (sorry, typing error)
>> If you want to extend your disk space by plugging in an extra
>> disk, the hardware RAID controller will probably detect it and
>> add it in his management, but will it be seen by FreeBSD?
> FreeBSD will see larger drive.
With what command can you see that FreeBSD had 'seen' it ?
Or is the the bsdlabel command? Is bsdlabel a partition management
program (such as GParted, Partition Magic)?
> you then have to fix partition table (use bsdlabel -e)
> fix c partition to be actually sized of whole drive, and then
> a) add new partition(s) for new space
> b) extend the size of last partition and use growfs
I guess here you mean 2 alternatives: a) using the new space for
new partition(s) leaving the existing as they are
or b) create no new partitions but extend the last partition to include
the new space, by using the growfs command ?
>> How can you make the added disk-space available for FreeBSD.
>> Can this be done without shutting down the system? How??
> i don't think FreeBSD can be told to reget device info from controller when
> partitions of that device are mounted. but i may be wrong
Hmm, man growfs says:
Currently growfs CAN ONLY ENLARGE UNMOUNTED FILE SYSTEMS.
DO NOT TRY ENLARGING A MOUNTED FILE SYSTEM, YOUR SYSTEM WILL PANIC
AND YOU WILL NOT BE ABLE TO USE THE FILE SYSTEM ANY LONGER.
If your FreeDSB only has swap and a / file system (with all users inside
/usr/home) or you set up FreeBSD with a swap, /, /var and /usr
filesystems (with users in /usr/home) and you want to grow a file
system (e.g. /usr to give the extra space to users) (scenario b))
I guess, you will need to go into single-user mode and boot from CD
with a FreeBSD in RAM to be able extend the (unmounted) file system /usr
Can scenario a) (making new file system for new space) be done in
multi-user mode, or only in single-user mode, will it need a reboot ??
Is there any document (besides the manual pages bsdlabel, growfs, ..)
that describes step-by-step what to do to grow an existing file system
of to add a new file system on newly added disk space ?
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