On 11/16/2020 01:23 PM, Jonathan Billings wrote:> On Sun, Nov 15, 2020 at 07:49:09PM -0500, H wrote: >> I have been having some problems with hardware RAID 1 on the >> motherboard that I am running CentOS 7 on. After a BIOS upgrade of >> the system, I lost the RAID 1 setup and was no longer able to boot >> the system. > The Intel RST RAID (aka Intel Matrix RAID) is also known as a > fakeraid. It isn't a hardware RAID, but instead a software RAID that > has a fancy BIOS interface. I believe that the mdadm tool can examine > the RAID settings, and you can look at /proc/mdstat to see its status, > although from what I remember from previous posts, it's better to just > let the BIOS think it's a JBOD and use the linux software RAID tools > directly. >I see, thank you. Right now I am running off one of the disks because of the mishap, I am also waiting for a systemboard replacement at which time I can decided whether to go with Linux software RAID, ie mdadm, or back to the Intel BIOS RAID. The latter lacks any progress indicators in BIOS when rebuilding an array which took around 20 hours for a 256 GB RAID 1 setup and it is annoying not to know the status of the rebuild etc. Could mdadm in a command window helped me answer that question? Also, it seemed that the BIOS RAID damaged the partition table on the disks - should I expect that this happens? My guess would be no but what do I know...
On Mon, 2020-11-16 at 18:06 -0500, H wrote:> On 11/16/2020 01:23 PM, Jonathan Billings wrote: > > On Sun, Nov 15, 2020 at 07:49:09PM -0500, H wrote: > > > I have been having some problems with hardware RAID 1 on the > > > motherboard that I am running CentOS 7 on. After a BIOS upgrade of > > > the system, I lost the RAID 1 setup and was no longer able to boot > > > the system. > > The Intel RST RAID (aka Intel Matrix RAID) is also known as a > > fakeraid. It isn't a hardware RAID, but instead a software RAID that > > has a fancy BIOS interface. I believe that the mdadm tool can examine > > the RAID settings, and you can look at /proc/mdstat to see its status, > > although from what I remember from previous posts, it's better to just > > let the BIOS think it's a JBOD and use the linux software RAID tools > > directly. > > > I see, thank you. Right now I am running off one of the disks because of the mishap, I am also waiting for a systemboard replacement at which time I can decided whether to go with Linux software RAID, ie mdadm, or back to the Intel BIOS RAID. > > The latter lacks any progress indicators in BIOS when rebuilding an array which took around 20 hours for a 256 GB RAID 1 setup and it is annoying not to know the status of the rebuild etc. Could mdadm in a command window helped me answer that question? > > Also, it seemed that the BIOS RAID damaged the partition table on the disks - should I expect that this happens? My guess would be no but what do I know...I'd use software raid rather the fakeraid. One of the advantages is that you are not limited to the mainboard and can use the disks in another machine if you need to. If you need to replace the board, you are not limited to one that provides a compatible fakeraid. Using software raid with mdadm will give you indication about the progress of rebuilds and checks by looking at /proc/mdstat, and you can automatically get an email in case a disk fails if so configured. Being informed about disk failures is relevant. I've used Linux software raid for at least 20 years and never had any problems with it other than questionable performance disadvantages compared to hardware raid. When a disk fails just replace it, and I've recently found that it can be impossible to get a rebuild started with hardware raid, which makes it virtually useless. I've never used the (Intel) fakeraid. Why would I? If you don't require Centos, you could go for Fedora instead. Fedora has btrfs as default file system now which has software raid built-in, and Fedora can have advantages over Centos.
Valeri Galtsev
2020-Nov-17 14:01 UTC
[CentOS] Intel RST RAID 1, partition tables and UUIDs
> On Nov 17, 2020, at 1:07 AM, hw <hw at gc-24.de> wrote: > > On Mon, 2020-11-16 at 18:06 -0500, H wrote: >> On 11/16/2020 01:23 PM, Jonathan Billings wrote: >>> On Sun, Nov 15, 2020 at 07:49:09PM -0500, H wrote: >>>> I have been having some problems with hardware RAID 1 on the >>>> motherboard that I am running CentOS 7 on. After a BIOS upgrade of >>>> the system, I lost the RAID 1 setup and was no longer able to boot >>>> the system. >>> The Intel RST RAID (aka Intel Matrix RAID) is also known as a >>> fakeraid. It isn't a hardware RAID, but instead a software RAID that >>> has a fancy BIOS interface. I believe that the mdadm tool can examine >>> the RAID settings, and you can look at /proc/mdstat to see its status, >>> although from what I remember from previous posts, it's better to just >>> let the BIOS think it's a JBOD and use the linux software RAID tools >>> directly. >>> >> I see, thank you. Right now I am running off one of the disks because of the mishap, I am also waiting for a systemboard replacement at which time I can decided whether to go with Linux software RAID, ie mdadm, or back to the Intel BIOS RAID. >> >> The latter lacks any progress indicators in BIOS when rebuilding an array which took around 20 hours for a 256 GB RAID 1 setup and it is annoying not to know the status of the rebuild etc. Could mdadm in a command window helped me answer that question? >> >> Also, it seemed that the BIOS RAID damaged the partition table on the disks - should I expect that this happens? My guess would be no but what do I know... > > I'd use software raid rather the fakeraid. One of the advantages is that > you are not limited to the mainboard and can use the disks in another machine > if you need to. If you need to replace the board, you are not limited to > one that provides a compatible fakeraid. > > Using software raid with mdadm will give you indication about the progress > of rebuilds and checks by looking at /proc/mdstat, and you can automatically > get an email in case a disk fails if so configured. Being informed about > disk failures is relevant. > > I've used Linux software raid for at least 20 years and never had any problems > with it other than questionable performance disadvantages compared to hardware > raid. When a disk fails just replace it, and I've recently found that it > can be impossible to get a rebuild started with hardware raid, which makes it > virtually useless. > > I've never used the (Intel) fakeraid. Why would I? > > If you don't require Centos, you could go for Fedora instead. Fedora has btrfs > as default file system now which has software raid built-in, and Fedora can have > advantages over Centos. >There are advantages in a bleeding edge one can find useful. There is some bleeding too, plausible, so don?t be surprised. Valeri> > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos