Cannot expand RAID 6 array on P824i-p controller

[duckiu]

hi ，

P824 cannot be expanded in the BIOS，But you can do this under MR Storage Administrator, I've done it successfully with windows.

It's actually migrating first and adding the new hard drive during the migration.

[dpevunov]

Hi dickiu,

I'm trying to do this through MR Storage Administrator. I posted screenshots from it.

[dpevunov]

Hello everybody!

Wanted to share with the others the story end.

We were able to add disks to RAID 6 using "Modify Array" procedure, described in 15.3.1.1 (https://support.hpe.com/hpesc/public/docDisplay?docLocale=en_US&docId=emr_na-a00095199en_us). The transformation took about 3 weeks. During this period we experienced big problems with I/O, descpite the fact that the transformation rate was set to 15% during business hours. You can find more info about setting the transformation priority here https://support.hpe.com/hpesc/public/docDisplay?docLocale=en_US&docId=emr_na-a00053315en_us.

We had to stop ALL I/O and set the transformation rate, BGI rate and rebuild rate to 100% during 2 weekends to speed-up the transformation process.  

We added 2 disks to RAID6 but not simultaneously. We did it 1 by 1 because it was first time and we didn't know what to expect. I think the process could take 2 weeks instead of 3 if we add 2 disks at once. 

And the most interesting what we've got in the end. The transformation finished. We rebooted the server and tryed to resize FS to the new size using resize2fs. The resize was successfull but we got errors during FS mount:

kernel: EXT-fs error (device sdb): ext4_mb_generate_buddy:757: group 266, block bitmap and bg descriptor incossistent: 352 vs 0 free clusters

EXT4-fs (sdb): ext4_check_descriptors: Block bitmap for group 0 overlaps block group descriptors

We were able to repair the superblock of the FS using e2fsck and to mount it but later this day we've got block corruption and the server began to reboot in a cycle. We stopped this only by disabling the resized FS in fstab. Then we switched the production database to the standby server.

We managed to repair the FS only by recreating RAID and loosing ALL PRODUCTION DATA on it. Now it is working OK without any corruptions. 

During all this hell we opened a support case with HPE. But we didn't get much help from them. The most interesing info that we've got from them is that this controller is based on the Broadcom chip and competelly differs from standard НРЕ Smart Array controlers. Any technical nuances of this controller should be found on the Broadcom site https://www.broadcom.com/support/knowledgebase/1211161503168/how-to-expand-an-array-on-megaraid-controllers-adding-drives-to-

So, think twice before bying and using this controller in the production environment!