Oracle Database Backup Cloud Service Primer

 One topic that has been coming a lot as customers look at options for offsite protected backups, is the use of the Oracle Database Backup Cloud Service.  This service can be used either directly from the database itself leveraging an RMAN tape library, or by performing a copy-to-cloud from the ZDLRA.  In this post I will try to consolidate all the information I can find on this topic to get you started.

Overview

The best place to start is by downloading, and reading through this technical brief. 

This document walks you through what the service is and how to implement it. Before you go forward with the Backup Cloud Service I suggest you download the install package and go through how to install it.

The key points I saw in this document are

• RMAN encryption is mandatory - In this brief you will see that the backups being sent to OCI MUST be encrypted, and the brief explains how to create an encrypted backup.  Included in the Backup Cloud Service is the use of encryption and compression (beyond basic compression) without requiring the ASO, or ACO license.
• How to install the client files - The brief explains the parameters that are needed to install the client files, and what the client files are that get installed. I will go into more detail later on explaining additional features that have been added recently.
• Config file settings including host - The document explains the contents of the configuration file used by the Backup Cloud Service library. It also explains how to determine the name of the host (OCI endpoint) based on the region you are sending the backups to.
• Channel configuration example - There is an example channel configuration to show you how to connect to the service.
• Best practices - The document includes sample scripts and best practices to use when using the Backup Cloud Service.
• Lifecycle policies and storage tiers - This is an important feature of using the Backup Cloud Service, especially for long term archival backups.  You most likely want have backups automatically moved to low cost archival storage after uploading to OCI.

NOTE: When using lifecycle polies to manage the storage tiers it is best to set the "-enableArchiving" and "-archiveAfterBackup" parameters when installing the backup module for a new bucket.  There are small metadata files that MUST remain in standard storage, and the installation module creates a lifecycle rule with the bucket that properly archives backup pieces, leaving the metadata in standard storage.

Download

The version of the library on OTN (at the time I am writing this) is NOT the current release of the library, and that version does not support retention lock of objects.

Please download the library from this location.

Documentation on the newer features can be found here, using retention lock can be found here, and there is a oci_readme.txt file that contains all the parameters available.

Updates

There were a few updates since the tech brief was written, and I will summarize the important ones here.  I also spoke the PM who is working on an updated brief that will contain this new information.

• newRSAKeyPair - The installer is now able to generate the key pair for you making it much easier to generate new key pair. In order to have the installer ONLY create a new key pair pair, just pass the installer the "walletDir" parameter.  The installer will generate both a public and private key, and place them in the walletDir (see below).

 /u01/app/oracle/product/19c/dbhome_1/jdk/bin/java -jar oci_install.jar -newRSAKeyPair -walletDir /home/oracle/oci/wallet 
Oracle Database Cloud Backup Module Install Tool, build 19.18.0.0.0DBBKPCSBP_2023-09-21
OCI API signing keys are created:
  PRIVATE KEY --> /home/oracle/oci/wallet/oci_pvt
  PUBLIC  KEY --> /home/oracle/oci/wallet/oci_pub
Please upload the public key in the OCI console.

Once you generate the public/private key, you can upload the public key to the OCI console. This will show you the fingerprint, and you can execute the installer using the private key file.

• "immutable-bucket" and "temp-metadata-bucket" - The biggest addition to library is the ability to support the use of retention rules on buckets containing backups.  The uploading of backups is monitored by using a "heartbeat" file, and this file is deleted when the upload is successful.  Because all objects in a bucket are locked, the "heartbeat" object must be managed from a second bucket without retention rules.  This is the temp-metadata-bucket.  When using retention rules you MUST have both buckets set in the config file.

NOTE: 

I ran into 2 issues when executing this script.

1)  When trying to execute the jar file, I used the default java version in my OCI tenancy that is located in "/user/bin". The installer received a java error

"java.lang.NoClassDefFoundError: javax/xml/bind/DatatypeConverter"

In order to properly execute the installer, I used the java executable located in $ORACLE_HOME/jdk/bin

2) When executing the jar file with my own RSA key that I had been previously used with OCI object storage, I received a java error.

Exception in thread "main" java.lang.RuntimeException: Could not produce a private key
at oracle.backup.util.FileDownload.encode(FileDownload.java:823)
at oracle.backup.util.FileDownload.addBmcAuthHeader(FileDownload.java:647)
at oracle.backup.util.FileDownload.addHttpAuthHeader(FileDownload.java:169)
at oracle.backup.util.FileDownload.addHttpAuthHeader(FileDownload.java:151)
at oracle.backup.opc.install.BmcConfig.initBmcConnection(BmcConfig.java:437)
at oracle.backup.opc.install.BmcConfig.initBmcConnection(BmcConfig.java:428)
at oracle.backup.opc.install.BmcConfig.testConnection(BmcConfig.java:393)
at oracle.backup.opc.install.BmcConfig.doBmcConfig(BmcConfig.java:250)
at oracle.backup.opc.install.BmcConfig.main(BmcConfig.java:242)
Caused by: java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException : algid parse error, not a sequence

I found that this was caused by the PKCS format. I was using a PKCS1 key, and the java installer was looking for a PKCS8 key.  The header in my private key file contained "BEGIN RSA PRIVATE KEY".

In order to convert my private PKCS1 key "oci_api_key.pem" to a PKCS8 key "pkcs8.key" I ran.

openssl pkcs8 -topk8 -inform PEM -outform PEM -nocrypt -in oci_api_key.pem -out pkcs8.key

Executing the install

The next step is to execute the install. For my install I also wanted configure a lifecycle rule that would archive backups after 14 days.  In order to implement this, I had the script create a new bucket "bsgtest".  Below is parameters I used (note I used "..." to obfuscate the OCIDs).

$ORACLE_HOME/jdk/bin/java -jar oci_install.jar -pvtKeyFile /home/oracle/oci/wallet/pkcs8.key -pubFingerPrint .... -tOCID  ocid1.tenancy.oc1... -host https://objectstorage.us-ashburn-1.oraclecloud.com -uOCID ocid1.user.oc1.... -bucket bsgtest -cOCID ocid1.compartment.oc1... -walletDir /home/oracle/oci/wallet -libDir /home/oracle/oci/lib -configFile /home/oracle/oci/config/backupconfig.ora -enableArchiving TRUE -archiveAfterBackup "14 days"

This created a new bucket "bsgtest" containing a lifecycle rule.

I then added a 14 day retention rule to this bucket, and created a second bucket "bsgtest_meta" for the temporary metadata. If you want to make this rule permanent you enable retention rule lock which I highlighted on the screenshot below.

I then updated the config file to use the metadata bucket because I set a retention rule on the main bucket. Note that there is also a parameter that determines how long archival objects are cached in standard storage before they are returned to archival storage.

OPC_CONTAINER=bsgtest
OPC_TEMP_CONTAINER=bsgtest_meta
OPC_AUTH_SCHEME=BMC
retainAfterRestore=48 HOURS

Testing

Once you execute the installer you will be able to begin backing up to OCI object storage.  Don't forget that you need to:

• Change the default device type to SBT_TAPE
• Change the compression algorithm. I recommend "medium" compression.
• Configure encryption for database ON.
• Configure the device type SBT_TAPE to send COMPRESSED BACKUPSET to optimize throughput and storage in OCI.
• Create a default channel configuration for SBT_TAPE (or allocate channels manually) that use the library that was downloaded, and point to the configuration file for the database.
• If you do not use ACO and don't have a wallet , manually set an encryption password in your session.

I recommend sending a "small" backup piece first to ensure that everything is properly configured.  My favorite command is

RMAN>backup incremental level 0 datafile 1;

Datafile 1 is always the system tablespace.

Below is what my configuration looks like for RMAN specifically for what I changed to use the Backup Cloud Service.

CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO 'SBT_TAPE';
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO '%F'; # default
CONFIGURE DEVICE TYPE 'SBT_TAPE' PARALLELISM 4 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS  'SBT_LIBRARY=/home/oracle/oci/lib/libopc.so ENV=(OPC_PFILE=/home/oracle/oci/config/backupconfig.ora)';
CONFIGURE ENCRYPTION FOR DATABASE ON;
CONFIGURE ENCRYPTION ALGORITHM 'AES256'; # default
CONFIGURE COMPRESSION ALGORITHM 'MEDIUM' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE;

Network Performance

One of the big areas that comes up with using the Backup Cloud Service, is understanding the network capabilities.

The best place to start is with this MOS note

How to measure network performance from RMAN for ZDLRA or Cloud Backups (Doc ID 2371860.1) It is a short note, but it shows you how to determine the throughput you can expect from a single stream/channel of data. Below is an example of how to use this based on my configuration.  I used it to test sending 1000M (1GB) of data.  From the results I can see that a single channel can send and receive 1GB in about 15 seconds.  This works out to about 240 GB/hr.

RMAN> run {
2> allocate channel foo device type sbt  PARMS  'SBT_LIBRARY=/home/oracle/oci/lib/libopc.so ENV=(OPC_PFILE=/home/oracle/oci/config/backupconfig.ora)';
3>  send channel foo 'NETTEST 1000M';
4> }

allocated channel: foo
channel foo: SID=431 device type=SBT_TAPE
channel foo: Oracle Database Backup Service Library VER=19.0.0.1

released channel: foo
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of send command at 11/22/2023 14:12:04
ORA-19559: error sending device command: NETTEST 1000M
ORA-19557: device error, device type: SBT_TAPE, device name:
ORA-27194: skgfdvcmd: sbtcommand returned error
ORA-19511: non RMAN, but media manager or vendor specific failure, error text:
   KBHS-00402: NETTEST sucessfully completed
KBHS-00401: NETTEST RESTORE: 1048576000 bytes received in 15068283 microseconds
KBHS-00400: NETTEST BACKUP: 1048576000 bytes sent

Executing Backups

Now to put it all together I am going to execute a backup of datafile 1.  My database is encrypted, so I am going to set a password along with the encryption key.

 set encryption on identified by oracle;

executing command: SET encryption

RMAN>  backup incremental level 0 datafile 1;

Starting backup at 22-NOV-23
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=404 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Oracle Database Backup Service Library VER=19.0.0.1
allocated channel: ORA_SBT_TAPE_2
channel ORA_SBT_TAPE_2: SID=494 device type=SBT_TAPE
channel ORA_SBT_TAPE_2: Oracle Database Backup Service Library VER=19.0.0.1
allocated channel: ORA_SBT_TAPE_3
channel ORA_SBT_TAPE_3: SID=599 device type=SBT_TAPE
channel ORA_SBT_TAPE_3: Oracle Database Backup Service Library VER=19.0.0.1
allocated channel: ORA_SBT_TAPE_4
channel ORA_SBT_TAPE_4: SID=691 device type=SBT_TAPE
channel ORA_SBT_TAPE_4: Oracle Database Backup Service Library VER=19.0.0.1
channel ORA_SBT_TAPE_1: starting incremental level 0 datafile backup set
channel ORA_SBT_TAPE_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/ACMEDBP/system01.dbf
channel ORA_SBT_TAPE_1: starting piece 1 at 22-NOV-23
channel ORA_SBT_TAPE_1: finished piece 1 at 22-NOV-23
piece handle=8t2c4fmi_1309_1_1 tag=TAG20231122T150554 comment=API Version 2.0,MMS Version 19.0.0.1
channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:35
Finished backup at 22-NOV-23

Starting Control File and SPFILE Autobackup at 22-NOV-23
piece handle=c-1654679317-20231122-01 comment=API Version 2.0,MMS Version 19.0.0.1
Finished Control File and SPFILE Autobackup at 22-NOV-23

Restoring

Restoring is very easy as long as you have the entries in your controlfile. If you don't then there is a 

 script included in the installation that can catalog the backup pieces and I go through that process here.

This also allows you to display what's in the bucket.

Buckets 1 vs many

If you look at what created when executing backup you will see that there is a set format for the backup pieces. Below are the 2 backup pieces that I created

• 8t2c4fmi_1209_1_1 - This is the backup of datafile 1 for my database ACMEDBP
• c-16546791317-20231122-01 - This is the controlfile backup for this database

Notice that the DB name is not in the name of the backup pieces, or in the visible nesting.

If you think about a medium sized database (let's say 100 datafiles), that has 2 weeks of backups (14 days), you would have 1,400 different backup pieces for the datafiles within the "sbt_catalog" directory.

My recommendation is to group small databases together in the same bucket (keeping the amount of backup pieces to a manageable level).

For large database (1,000+ datafiles), you can see where a 30 day retention could become 30,000+ backup pieces.

Having a large number of objects within a bucket increases the time to report the available backup pieces.  There is no way to determine which database the object is a member of without looking at the metadata.

Keep this in mind when considering how many buckets to create.