Back up using Azure Application Consistent Snapshot tool
This article provides a guide for running the backup command of the Azure Application Consistent Snapshot tool that you can use with Azure NetApp Files.
A storage snapshot based backup is run using the azacsnap -c backup
command. This command performs the orchestration of a database consistent storage snapshot on the DATA volumes, and a storage snapshot (without any database consistency setup) on the OTHER volumes.
For DATA volumes azacsnap
prepares the database for a storage snapshot, then it takes a storage snapshot for all configured volumes, finally it tells the database the snapshot is complete. It also manages any database entries which record snapshot backup activity (for example, SAP HANA backup catalog).
The -c backup
command takes the following arguments:
--volume=
type of volume to snapshot, this parameter may containdata
,other
, orall
data
snapshots the volumes within thedataVolume
stanza of the configuration file.- data Volume Snapshot process
- put the database into backup-mode.
- take snapshots of the Volumes listed in the configuration file's
"dataVolume"
stanza. - take the database out of backup-mode.
- perform snapshot management.
- data Volume Snapshot process
other
snapshots the volumes within theotherVolume
stanza of the configuration file.- other Volume Snapshot process
- take snapshots of the Volumes listed in the configuration file's
"otherVolume"
stanza. - perform snapshot management.
- take snapshots of the Volumes listed in the configuration file's
- other Volume Snapshot process
all
snapshots all the volumes in thedataVolume
stanza and then all the volumes in theotherVolume
stanza of the configuration file. The processing is handled in the order outlined as follows:- all Volumes Snapshot process
- data Volume Snapshot (same as the normal
--volume data
option)- put the database into backup-mode.
- take snapshots of the Volumes listed in the configuration file's
"dataVolume"
stanza. - take the database out of backup-mode.
- perform snapshot management.
- other Volume Snapshot (same as the normal
--volume other
option)- take snapshots of the Volumes listed in the configuration file's
"otherVolume"
stanza. - perform snapshot management.
- take snapshots of the Volumes listed in the configuration file's
- data Volume Snapshot (same as the normal
- all Volumes Snapshot process
Note
By creating a separate config file with the boot volume as the otherVolume, it's possible for
boot
snapshots to be taken on an entirely different schedule (for example, daily).--prefix=
the customer snapshot prefix for the snapshot name. This parameter has two purposes. Firstly provide a unique name for grouping of snapshots. Secondly to determine the--retention
number of storage snapshots that are kept for the specified--prefix
.Important
Only alpha numeric ("A-Z,a-z,0-9"), underscore ("_") and dash ("-") characters are allowed.
--retention
the number of snapshots of the defined--prefix
to be kept. Any extra snapshots are removed after a new snapshot is taken for this--prefix
.--trim
available for SAP HANA v2 and later, this option maintains the backup catalog and on disk catalog and log backups. The number of entries to keep in the backup catalog is determined by the--retention
option above, and deletes older entries for the defined prefix (--prefix
) from the backup catalog, and the related physical logs backup. It also deletes any log backup entries that are older than the oldest non-log backup entry. This--trim
operation helps to prevent the log backups from using up all available disk space.Note
The following example command will keep 9 storage snapshots and ensure the backup catalog is continuously trimmed to match the 9 storage snapshots being retained.
azacsnap -c backup --volume data --prefix hana_TEST --retention 9 --trim
[--flush]
an option to request the operating system kernel to flush I/O buffers for volumes after the database is put into "backup mode". In prior versions we used the "mountpoint" values to indicate volumes to flush, with AzAcSnap 10 the--flush
option will take care of it. Therefore this key/value ("mountpoint") can be removed from the configuration file.- On Windows volumes which are labelled as "Windows" or "Recovery", and are NTFS will not be flushed. You can also add "noflush" to the volume label and it will not be flushed.
- On Linux all I/O is flushed using the Linux
sync
command.
Running the following example on the same host running the database will:
- Put the database into "backup mode".
- Request an operating system kernel flush of I/O buffers for local volumes (see operating system specific details).
- Take a storage snapshot.
- Release the database from "backup mode".
azacsnap -c backup --volume data --prefix hana_TEST --retention 9 --trim --flush
[--ssl=]
an optional parameter that defines the encryption method used to communicate with SAP HANA, eitheropenssl
orcommoncrypto
. If defined, then theazacsnap -c backup
command expects to find two files in the same directory, these files must be named after the corresponding SID. Refer to Using SSL for communication with SAP HANA. The following example takes ahana
type snapshot with a prefix ofhana_TEST
and keeps9
of them communicating with SAP HANA using SSL (openssl
).azacsnap -c backup --volume data --prefix hana_TEST --retention 9 --trim --ssl=openssl
[--configfile <config filename>]
is an optional parameter allowing for custom configuration file names.
The duration of a snapshot backup is independent of the volume size, with a 10-TB volume being snapped within the same approximate time as a 10-GB volume.
The primary factors impacting overall execution time are the number of volumes to be snapshot and any
changes in the --retention
parameter (where a reduction can increase the execution time as excess
snapshots are removed).
In the example configuration provided for Azure Large Instance, snapshots for the two volumes took less than 5 seconds to complete. For Azure NetApp Files, snapshots for the two volumes would take about 60 seconds.
Note
If the --retention
is significantly reduced from the previous time azacsnap
is run
(for example, from --retention 50
to --retention 5
), then the time taken will increase as azacsnap
needs to remove the extra snapshots.
azacsnap -c backup --volume data --prefix hana_TEST --retention 9 --trim
The command doesn't output to the console, but does write to a log file, a result file,
and /var/log/messages
.
In this example, the log file name is azacsnap-backup-azacsnap.log
(see Log files).
When running the command -c backup
with the --volume data
option, a result file is also generated as a file to allow
for quickly checking the result of a backup. The result file has the same base name as the log file, with .result
as its suffix.
In this example, the result file name is azacsnap-backup-azacsnap.result
and contains the following output:
cat logs/azacsnap-backup-azacsnap.result
Database # 1 (H80) : completed ok
The /var/log/messages
file contains the same output as the .result
file. See the following
example (run as root):
grep "azacsnap.*Database" /var/log/messages | tail -n10
Jul 2 05:22:07 server01 azacsnap[183868]: Database # 1 (H80) : completed ok
Jul 2 05:27:06 server01 azacsnap[4069]: Database # 1 (H80) : completed ok
Jul 2 05:32:07 server01 azacsnap[19769]: Database # 1 (H80) : completed ok
Jul 2 05:37:06 server01 azacsnap[35312]: Database # 1 (H80) : completed ok
Jul 2 05:42:06 server01 azacsnap[50877]: Database # 1 (H80) : completed ok
Jul 2 05:47:06 server01 azacsnap[66429]: Database # 1 (H80) : completed ok
Jul 2 05:52:06 server01 azacsnap[82964]: Database # 1 (H80) : completed ok
Jul 2 05:57:06 server01 azacsnap[98522]: Database # 1 (H80) : completed ok
Jul 2 05:59:13 server01 azacsnap[105519]: Database # 1 (H80) : completed ok
Jul 2 06:02:06 server01 azacsnap[114280]: Database # 1 (H80) : completed ok
azacsnap -c backup --volume other --prefix logs_TEST --retention 9
The command doesn't output to the console, but does write to a log file only. It does not write
to a result file or /var/log/messages
.
In this example, the log file name is azacsnap-backup-azacsnap.log
(see Log files).
Note
The use of another configuration file (--configfile bootVol.json
) which contains only
the boot volumes.
azacsnap -c backup --volume other --prefix boot_TEST --retention 9 --configfile bootVol.json
Important
For Azure Large Instance, the configuration file volume parameter for the boot volume might not be visible at the host operating system level. This value can be provided by Microsoft Operations.
The command doesn't output to the console, but does write to a log file only. It does not write
to a result file or /var/log/messages
.
In this example, the log file name is azacsnap-backup-bootVol.log
(see Log files).
The log file name is constructed from the following "(command name)-(the -c
option)-(the config filename)". For example, if running the command azacsnap -c backup --configfile h80.json --retention 5 --prefix one-off
then the log file is called azacsnap-backup-h80.log
. Or if using the -c test
option with the same configuration file (e.g. azacsnap -c test --configfile h80.json
) then the log file is called azacsnap-test-h80.log
.
Note
Log files can be automatically maintained using this guide.