Raid 5 PowerEdge Perc 6/i 1 disk failure 2 discs Foreign

Noodlelord,

You would indeed need to import the foreign, and if that doesn't work due to the changes you may need to retag (delete and recreate VD as previous configured without initialization) the Virtual Disk. A good rule of thumb with foreign configurations is that if a Virtual Disk is bootable with a foreign you would clear the foreign, if the Virtual Disk is not booting with a foreign then you would need to try importing the foreign. 

Hi, thank you for the quick response last time. Importing the Raid did not work so I went for the retag. I deleted the VD then I went to build a new VD. I added all my drives and then selected the add hot spare. When I went to the hot spare page there was none available. I realized that I cant add all drives to the array. I hit cancel. On VD Mgmt page there was a percentage indicator where you would hit fast load or rebuild. (I might have that name wrong) I noticed that I did not have my hot spare and thought to not add it in my array this time. I deleted this VD and started over. I then saw that my drive 6 was foreign and says Virtual disk 255. Drive 6 says no error in the S.M.A.R.T status. I don't know what this means and I can not get it back in my RAID. Could you help me on this? 

What you would need to do is reconfigure the Virtual Disk, you would need to do this with the 5 working drives, as well as the replacement. This is because you need the same amount of drives as it was configured with previously, and since the one drive failed you need another disk to retag with. Once you create the 6 drive VD you do NOT initialize it ( that will format drives and you will lose data), once the VD is created then you have to remove the replacement drive before you try to boot. You do this as there is no data on the drive and loading the VD with it will corrupt the data. Once you boot successfully then you can try reinstalling the replacement while the server is up, and see if it will rebuild.

In the controller BIOS you can clear the foreign for the disk, but you may want to consider data recovery as well, as rebuilding the drive may have caused data loss and anything further could cause more. With the one VD member still being in foreign and the drive was rebuilt without it, then the data wont be intact. You normally want to wait to rebuild it until we powered it up to the OS.

I'm in a similar situation, except my foreign disk does show SMART errors.

It's RAID5, one failed disk, one foreign.

Do the same rules apply, try to import the foreign configuration and then retag the configuration if it doesn't boot?

I'm pretty sure I understand how to replace the failed disk, mark it as a global HS and tell it to give priority to the enclosure to rebuild it.  I'm assuming once I do that with the failed drive, I can repeat the process with the drive that has the SMART errors.

Thanks for your help.

Hi CBP7,

just to give some clarification about the foreign config.

pd05 has a foreign config, which means it was used already in a RAID array and the config of that array is still stored on this hard drive. The PERC now reads this information and see that it does not match the actual configuration, so it marks the drive with a foreign config. 

Importing this configuration will overwrite your actual one. In this case you need to clear that foreign config on this pd and mark is as global hot-spare in order to get the rebuild running.

Best regards,
Stefan

That doesn't sound like good news... All 8 were originally part of a single RAID5.

From what I understand, it's not possible to lose 2 disks and still retain the data.

#7 definitely seems like it's gone, but I was hoping #5 could be used to rebuild the array. It just has SMART errors. Are you saying #5 is lost too?

...and followup question, if we decided to start from scratch using a backup, could we create a RAID5 using 8 SATA SSDs on the PERC H710?

I'm reading on other fora that they may need an interposer to work with the SAS connectors, but I'm not sure if that's true or not.

We are looking at the Dell R0KXM 100GB SSDs with SATA 3. Will those work with the PERC H710?

RAID 5 has single-disk fault tolerance. Lose a second, and it’s dead. RAID 5 in general is dead, do not use it.

IF ALL THE DRIVES ARE ORIGINAL DRIVES TO THIS ARRAY! : Boot to your CTRL-R utility, highlight the controller, F2, Foreign, IMPORT (you should also have stuff in the Foreign View tab to corroborate the config you are importing).

Yes, you can create a new RAID 5 on the controller, and I’ll allow you to configure a RAID 5 only because you are using small enterprise-class SSD’s (allow = wink ;)), as it meets my requirements for RAID 5 today: 1) smaller than 750GB, 2) SSD, 3) certified/validated drives for the controller ... BUT in general get it into your conscious now – it is 2020 and RAID 5 is dead and should not be used.

Interposers are not necessary unless your other SATA drives have them too.

Also, don’t expect full SSD performance from this setup, as the PERC 6 does not fully support SSD AND it is only a 3Gbps controller. It will be better than HDD, but it will not help the SSD’s achieve their greatest potential.