RAID and /boot partitions

[Bill Davidsen]

redhatdude at bellsouth.net wrote:
> -------------- Original message ----------------------
> From: redhatdude at bellsouth.net
>>
>>
>> -------------- Original message ----------------------
>> From: Bill Davidsen <davidsen at tmr.com>
>>> redhatdude at bellsouth.net wrote:
>>>> Hi,
>>>> When creating a RAID 1 in F9.
>>>> Does it make sense to make the /boot partition on both discs a RAID too?
>>> I have /boot and / as RAID 1 (dm-0 and dm-1). If I disconnect one of the 
>>> drives, the computer freezes. Isn't the RAID supposed to keep it running?
>>>> I'm really new to this, so any help is appreciated.
>>>>
>>> Are you sure /boot is on a raid partition, and not on a dm pseudo 
>>> device? If you created a partition on your drives, made a raid-1 of the 
>>> two partitions (100-200MB is good), and then did whatever with the rest 
>>> of your disk, you should be fine.
>>>
>>> If you made one huge raid array and used dm to break it up, you are not 
>>> fine. Do "cat /proc/mdstat" and see that there is a small raid-1 for 
>>> boot, and "df" to check that /dev/mdX is mounted on /boot. If that's the 
>>> case you should be good, otherwise you probably don't boot off one drive.
>>>
>>> NOTE: your BIOS may not boot off the 2nd drive if the 1st drive is 
>>> present and has data errors, should if the 1st drive is dead. Some BIOS 
>>> do, some don't.
>>>
>>> -- 
>>> Bill Davidsen <davidsen at tmr.com>
>>>    "We have more to fear from the bungling of the incompetent than from
>>> the machinations of the wicked."  - from Slashdot
>> This is the output of df.
>>
>> Filesystem           1K-blocks      Used Available Use% Mounted on
>> /dev/md1             470535632   3951984 442681744   1% /
>> /dev/md0                 99099     12499     81484  14% /boot
>> tmpfs                  2032168        48   2032120   1% /dev/shm
>>
>> And this is the output of cat /proc/mdstat 
>> Personalities : [raid1] [raid6] [raid5] [raid4] 
>> md0 : active raid1 sdb1[1] sda1[0]
>>       102336 blocks [2/2] [UU]
>>       
>> md1 : active raid1 sda3[0] sdb3[1]
>>       478038080 blocks [2/2] [UU]
>>       
>> unused devices: <none>
>>
>>
>> I have two drives with /boot and /
>> If I unplug the first one, the system remains up and running. If I however 
>> unplug the second one, the system becomes unstable, X crashes, and eventually 
>> the system becomes irresponsive.
>> Why does this happen with one disk only?
>> Thanks,
>> EJ
>>
>>
>> -- 
>> fedora-list mailing list
>> fedora-list at redhat.com
>> To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
> 
> To answer my own question.
> The problem is that the swap partition is only on one disk and it's not RAIDed. So when I unplug the drive with the swap partition, the system goes down.
> The next step would be to create a RAID for swap and make the system use it.
> EJ
> 
> 
Good catch, just for completeness, using a raid 10,f2 swap seems 
fastest, but the last Fedora recovery CD I tried didn't start it the way 
it does raid-1. I didn't need it, and could start it by hand, but if you 
have a low memory system it could be an issue.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot