Hello,
We are using btrfs filesystem on local disks (RAID 1) as underlying filesystem to host our Oracle 12c datafiles.
This allow us to cold backup databases via snapshot in a few seconds and benefit from higher performance than over Linux filesystem formats.
This is the problem we meet: Oracle regularly crashes with error of this 2 types, the errors occur on different physical machines with same softwares:
ORA-63999: data file suffered media failure
ORA-01114: IO error writing block to file 99 (block # 99968)
ORA-01110: data file 99: '/oradata/PS92PRD/data/pcapp.dbf'
ORA-27072: File I/O error
Linux-x86_64 Error: 17: File exists
Additional information: 4
Additional information: 99968
And
ORA-63999: data file suffered media failure
ORA-01114: IO error writing block to file 99 (block # 99994)
ORA-01110: data file 99: '/oradata/PS92PRD/data/pcapp.dbf'
ORA-27072: File I/O error
Linux-x86_64 Error: 5: Input/output error
Additional information: 4
Additional information: 99994
It nevers append with over filesystem types, all the hardware has been checked.
I suspect a Btrfs activated feature via our mount options instead of a bug: Oracle see a ghost or a duplicated bloc even if copy on cow feature is disabled.
Here are few details of the system:
Mount options: defaults,nofail,nodatacow,nobarrier,noatime
uname -a:
Linux 3.10.0-514.10.2.el7.x86_64 #1 SMP Fri Mar 3 00:04:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
btrfs -version: btrfs-progs v4.9.1
btrfs fi show:
Label: 'oradataBtrfs'
Total devices 1 FS bytes used 1.98TiB
devid 1 size 3.18TiB used 2.02TiB path /dev/sdb1
Thank you very much for your advice.
Philippe Houttemane
System, network and DBA engineer.
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