[CentOS] BIOS RAID0 and differences between disks

Thu Nov 12 01:58:02 UTC 2020
H <agents at meddatainc.com>

On 11/04/2020 10:21 PM, John Pierce wrote:
> is it RAID 0 (striped) or raid1 (mirrored) ??
> if you wrote on half of a raid0 stripe set, you basically trashed it.
> blocks are striped across both drives, so like 16k on the first disk, then
> 16k on the 2nd then 16k back on the first, repeat (replace 16k with
> whatever your raid stripe size is).
> if its a raid 1 mirror, then either disk by itself has the complete file
> system on it, so you should be able to remirror the changed disk onto the
> other drive.   you MUST do that re-mirror because your two disks are no
> longer identical, and reads will alternate between them, so some reads will
> get new data and others will get old data, which will be highly chaotic.
> On Wed, Nov 4, 2020 at 6:18 PM H <agents at meddatainc.com> wrote:
>> My computer running CentOS 7 is configured to use BIOS RAID0 and has two
>> identical SSDs which are also encrypted. I had a crash the other day and
>> due to a bug in the operating system update, I am unable to boot the system
>> in RAID mode since dracut does not recognize the disks in grub. After
>> modifying the grub command line I am able to boot the system from one of
>> the harddisks after entering the LUKS password, seemingly without any
>> problems but am obviously not running in RAID0 mode. When I booted in
>> single-disk mode I am sure there were some new files created on the single
>> SSD the system sees but I fairly quickly shut it down until this can be
>> fixed.
>> My question is: once the operating system fix has been released and I can
>> once again boot in BIOS RAID0 mode and decrypting both SSDs (same password
>> entered only once of course), how will the BIOS RAID0 react? How will it
>> handle new files on one disk, altered timestamps etc.?
>> Thanks.
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How do I do the remirroring once the system is working again? I filed a bug report on bugs.centos.org (https://bugs.centos.org/view.php?id=17830#c37850) but I could use some more assistance to take this further...

It was suggested that "if no kernel boots any more, I am pretty sure that your initial ramdisks were rebuild without including a kernel module required by LUKS.you should rebuild them , forcing dracut to include the missing driver. And in the process you might as well upgrade to centos 7.9, kernel 3.10.0-1160.2.2.el7.x86_64 is already available in the CR repository."

Unfortunately I do not know how do the above... And I do not know which drivers are missing that I need to include...

If anyone would be able to tell me the specific steps I will attempt to do the above.

Thank you in advance.