Veritas InfoScale™ 7.4 Solutions Guide - Linux

Enabling the atomic write I/O support for MySQL for VxFS file systems on VxVM volumes

1. Install the Fusion ioMemory card and enable atomic write support on the SSD.

   For information, see the SanDisk documentation.

2. Bring the SanDisk devices under VxVM control, as follows:

   • Discover the devices:

      # vxdisk scandisks

   • Display the devices that are available for VxVM use:

     # vxdisk list

     For example:

     # vxdisk list
     DEVICE 					TYPE 					DISK GROUP STATUS 
     fiodrive0_1 auto:none -    -     online invalid ssdtrim atomic-write

   • Initialize the disks:

     # /etc/vx/bin/vxdisksetup -i SanDisk_device

   • Verify that the disks are under VxVM control and have atomic write support:

     # vxdisk list

     For example:

     # vxdisk list
     DEVICE 					TYPE 						   DISK  GROUP STATUS 
     fiodrive0_1 auto:cdsdisk  -     -     online ssdtrim atomic-write

3. Add the device to a disk group. The disk group can include both SSDs and HDDs.

   • If you do not have a disk group, create the disk group:

     # vxdg init diskgroup dev1=fiodrive0_1

   • If you already have a disk group, add the device to the disk group:

     # vxdg -g diskgroup adddisk fiodrive0_1

4. Create the atomic write capable volume:

   # vxassist -A -g diskgroup make volume length mediatype:ssd

   Where:

   the -A option creates an atomic write capable volume of concatenated layout, on the atomic write capable disks.

5. Verify that the volume is atomic write capable:

   # vxprint -g diskgroup -m volume | grep atomic
   atomic_wr_capable=on 
   atomic_wr_iosize=16

   Where:

   atomic_wr_capable attribute indicates whether or not the volume supports atomic writes

   atomic_wr_iosize indicates the supported size of the atomic write I/O.

6. Create a VxFS file system over the atomic write capable volume.

   # mkfs.vxfs /dev/vx/rdsk/diskgroup/volume

7. Mount the file system at an appropriate location:

   # mount.vxfs /dev/vx/dsk/diskgroup/volume /mnt1

8. Configure the MySQL application with atomic write I/O support.
9. Configure the MySQL application to place the data file on the VxFS mount point.
10. Start the MySQL server.
11. Verify that MySQL is running with atomic write support using the following query:

    # mysql MariaDB [(none)]> select @@innodb_use_atomic_writes ; 
    +---------------------------+ 
    | @@innodb_use_atomic_writes| 
    +---------------------------+ 
    |                         	1| 
    +---------------------------+ 
    1 row in set (0.00 sec)