[CentOS] BIOS RAID0 and differences between disks

Thu Nov 12 02:23:26 UTC 2020
H <agents at meddatainc.com>

On November 11, 2020 8:58:02 PM EST, H <agents at meddatainc.com> wrote:
>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,
>> 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
>> system on it, so you should be able to remirror the changed disk onto
>> other drive.   you MUST do that re-mirror because your two disks are
>> 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
>> 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
>>> identical SSDs which are also encrypted. I had a crash the other day
>>> due to a bug in the operating system update, I am unable to boot the
>>> in RAID mode since dracut does not recognize the disks in grub.
>>> modifying the grub command line I am able to boot the system from
>one of
>>> the harddisks after entering the LUKS password, seemingly without
>>> problems but am obviously not running in RAID0 mode. When I booted
>>> single-disk mode I am sure there were some new files created on the
>>> SSD the system sees but I fairly quickly shut it down until this can
>>> 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
>>> entered only once of course), how will the BIOS RAID0 react? How
>will it
>>> handle new files on one disk, altered timestamps etc.?
>>> Thanks.
>>> _______________________________________________
>>> CentOS mailing list
>>> CentOS at centos.org
>>> https://lists.centos.org/mailman/listinfo/centos
>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.
>CentOS mailing list
>CentOS at centos.org

I should have corrected the previous info, it is RAID1, ie mirroring, not RAID0.