Host Arkeia Catalog Index on SSD

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Contents

Introduction

Hosting the Arkeia Catalog Index can increase backup speeds by as much as 50% over traditional hard disks.

IMPORTANT NOTE TO CUSTOMERS!
This documents should ONLY be used as a "basic guideline" to hosting the WD Arkeia Catalog Index on SSD.
It should not be used as a definitive guide to adding, formatting and managaging SSD devices.
The WD Arkeia Support Team DOES NOT provide system administration and/or SSD formating or troubleshooting support.

Advantages of SSD over HDD

Some Advantages of SSD over HDD are:

  • Fast read speeds - 2-3x faster than modern desktop HDDs (7,200 RPM using SATA2 interface).
  • Sustained read speeds - HDD performance tapers off as the drive heads move from the outer edges to the center of HDD platters.
  • Minimal access time - approximately 100x faster than an HDD.
  • High degree of reliability - RAID 1 is recommended
  • No moving parts.
  • Minimal heat production.

SSD Resources

The following resources can be used to obtain more information about SSD.

TRIM

TRIM SUPPORT IS MANDATORY!

A TRIM command allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally.
Before selecting an SSD device, ensure that your environment supports TRIM.

Linux Kernel

TRIM SUPPORT IS MANDATORY!

The Linux 2.6.36 kernel added discard support for ext4 when there is no journal using the “discard” mount option.
TRIM support fof XFS was introduced in kernel 2.6.38.

* 2.6.33: btrfs, ext4
* 2.6.33: btrfs, ext4      (including no journal mode)
* 2.6.37: btrfs, ext4      (including no journal mode and batched discard)
* 2.6.38: btrfs, ext4, xfs (including no journal mode and batched discard)

SSD Device

TRIM SUPPORT IS MANDATORY!

SATA SSD

When using a SATA SSD, the Linux kernel requires the SATA controller set to AHCI mode to use trim support.
Most motherboards have an option in the BIOS or UEFI, just make sure its set for AHCI.

Please reference your Manufacturers SSD User Guide or contact their support for details.

PCIe SSD

When using a PCIe SSD, ensure the PCIe controller from the vendor supports Linux and TRIM.

Please reference your Manufacturers PCIe Controller User Guide or contact their support for details.

SSD RAID

If your SSD devices supports RAID 1, please enable RAID 1 support in your device BIOS.

Please reference your Manufacturers SSD User Guide or contact their support for details.

SSD Configuration

Firmware Updates

Update the the firmware to the latest release provided by your SSD Vendor prior to formatting the device.

Please reference your Manufacturers SSD User Guide or contact their support for details.

Used SSD

This document assumes the SSD is brand new, never been used and does not require a secure erase.
If your SSD has been used, then a secure erase may be required.

The Secure Erase / Clearing Memory Cells is beyond the scope of this document.

Resource for SSD Memory Cell Clearing

SSD Installation

1) Power off your server
2) Install the SSD device
3) Power on the server
4) Go into the BIOS and

   * enable AHCI for SATA SSD
   * set PCIe SSD to RAID 1 in the BIOS

5) Boot the server

Verify TRIM Support

Use the following command to verify that your SSD support TRIM

hdparm -I /dev/sda | grep "TRIM"

Data Set Management TRIM supported (limit 16 blocks)

SSD Formatting

Locate your SSD device in dmesg or the partition manager of your choice.

EXAMPLE

[root]# dmesg | grep sd

sd 1:0:0:0: [sdc] Write Protect is off
sd 1:0:0:0: [sdc] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sdc: sdc1
sd 1:0:0:0: [sdc] Attached SCSI disk

Format the using XFS.
XFS is suitable for the Arkeia Catalog Index because of it's ability to allocated Inodes efficiently.

[root]# mkfs.xfs /dev/sdc

/dev/sdc is entire device, not just one partition!
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
29294592 inodes, 58569440 blocks
2928472 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
1788 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

Mount Options

The following mount options should be used for SSD devices

/dev/sdc      = defines the SSD device
/ssd          = defines the mount point
xfs           = defines the file system
nodiscard     = nodiscard disables online TRIM
noatime       = reduces writes
nodiratime    = reduce writes

IMPORTANT TRIM NOTE:

We have disabled online TRIM for performance purpose.
When files are deleted with online TRIM, it will immediately do the trimming and therefore it is much slower than performing a manual TRIM once per day using a cron entry.

File System Mounting

Create a mount point for the SSD device

[root]# mkdir /ssd


Manual Mount Test

Manually mount the SSD device to verify access

[root]# mount -t xfs /dev/sdc /ssd -o noatime,nodiratime,nodiscard
[root]# mount | grep ssd
/dev/sdc 250G 0G 250G 1% /ssd

[root]# cp /etc/hosts /ssd/hosts

/etc/fstab entry

Add a new entry in the /etc/fstab file to auto mount the SSD device using the suggestion options.

[root]# cd /etc
[root]# cp fstab fstab.bkp
[root]# vi fstab

/dev/sdc        /ssd                xfs defaults,nodiscard,noatime,nodiratime    0 2

Reboot the Server to verify the entry in fstab automounts the SSD.

[root]# mount | grep ssd

/dev/sdc 250G 0G 250G 1% /ssd

IMPORTANT STEP! TRIM cron entry

Activating TRIM once a day os the SSD is more efficient than having TRIM activated when mounted.

Locate the "fstrim" commany on your system

[root]# locate fstrim
/sbin/fstrim

Create a daily cron job that executes the /sbin/fstrim command

[root]# crontab -e
## Run TRIM on the SSD once per day at noon time (outside of the backup window)
* 12 * * * /sbin/fstrim /ssd

Catalog Index Move

This section provides the steps recommend for moving and existing Arkeia Catalog Index.

By default, the Arkeia Index is located in /opt/arkeia/server/dbase/o3dbtree. A new index will contain no data, but an existing index will contain the backup history.

Stop Arkeia Software to ensure that no backup jobs are running during the index move process

[root]# /opt/arkeia/bin/arkboot stop
[root]# killall https
[root]# killall arktrans

  • If your installation of Arkeia is brand new, then you can skip the index purge process.
  • If your installation of Arkeia is in production, then you'll want to purge the index to remove unused data structures.

Purging the Arkeia Index will remove all unused structures which will provide less data to move to the SSD, but it will also help increase Arkeia Performance.
If your index has been used for production backups, please use the arkdbchk -p command and let it complete 100%

Get the size of the current index before the purge

[root]# du -sh /opt/arkeia/server/dbase/o3dbtree
50G /opt/arkeia/server/dbase/o3dbtree 

Run the purge command

[root]$ /opt/arkeia/bin/arkdbchk -p

Get the size of the index after the purge to see the space savings

[root]# du -sh /opt/arkeia/server/dbase/o3dbtree
20G /opt/arkeia/server/dbase/o3dbtree 

Rename the Index

[root]# cd /opt/arkeia/server/dbase
[root]# mv o3dbtree o3dbtree.ORG

Copy the Arkeia o3dbtree directory to the SSD

[root]# cd /opt/arkeia/server/dbase
[root]# cp -R o3dbtree.ORG /ssd/o3dbtree

Once the copy has completed, verify the size of /ssd/o3dbtree

[root]# du -sh /ssd/o3dbtree
20G /ssd/o3dbtree 

Create the link to the new Arkeia Index located on SSD

[root]# cd /opt/arkeia/server/dbase
[root]# ln -s /ssd/o3dbtree o3dbtree

Verify the link is active

[root]# ls -latr
lrwxrwxrwx 1 root root 14 Oct 16 13:07 o3dbtree -> /ssd/o3dbtree/ 

Start Arkeia

[root]# /etc/init.d/arkeia start
[root]# /etc/init.d/arkwui start

Open the Arkeia WebUI and verify the index at the Restore Screen.
Ensure that all backup, replication and restore processes are successful.

Once complete, delete o3dbtree.ORG or maintain it as a source copy.

 [root]# cd /opt/arkeia/server/dbase
 [root]# rm -rf o3dbtree.ORG
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