How to increase Browse and Retention Time of a Save set:

nsrmm [-w ssbrowse] [-e ssretent] -S



There are few consideration
We cannot make the browse time longer than the retention time.
We cannot extend the browse time if the browse time has already expired.



nsrmm -d -S

Deletes the client file indexes and media database entries from the NetWorker
databases for ssid/cloneid saveset.

What is DD Boost ??
DD Boost is a software add-on to the Domain Hardware.It perform below actions:-

1. It distributes some of the steps in  dedup process to media server or storage node.  This reduces the LAN traffic and weirdly the CPU load on the media server and DD.
2. Backup aware replication – Using the OST* standard the DD can be sent commands from an OST compatible application to initiate the replication of backups.  This way the backup app is aware of all the copies of data even though the DD performed the replication process.
3. Link Aggregation and Failover – The ports on the DD can be put into a DD Boost group meaning that the DD Boost software client on the host will balance the network traffic between them.  This improves the performance of backups. 

*OST

The OST API is protocol independent, meaning the hardware providers can utilize OST over whatever protocols are best suited for their devices including Fibre Channel, TCP/IP or SCSI.

The OST API provides 4 key features but the hardware vendors are not required to support all of them but rather just select the ones most suited for their devices.

OpenStorage Features

Direct Copy to dedicated tape drives

Direct Copy to shared tape drives

Optimized Duplication

Optimized Synthetics

One manufacturer that has strongly embraced OST is Quantum with their latest DXI Series appliances supporting both Optimized Duplication and Direct Copy to Shared Tape Drives. Using these features Quantum is able to replicate between DXI appliances or backup directly from a DXI to a tape library all while keeping NetBackup aware and the catalog consistent.

DB2 Restore in AIX Environment

First of all we need below things

Source Server:P30

Destination Server:S30

Date of which backup required: Latest

Please take configuration and registry backup of database before proceeding to restore.

Step1:-Login on destination server with db2 user or root and execute below command.

db2 "RESTORE DATABASE <Source Server instance name>LOAD '/usr/lib/libnsrdb2.so' OPEN 6 SESSIONS OPTIONS '@<configuration files> REDIRECT generate script ./hello.ddl

e.g.

db2 "RESTORE DATABASE P30 LOAD '/usr/lib/libnsrdb2.so' OPEN 6 SESSIONS OPTIONS '@/db2/db2s30/DB2_CFG_P30_restore' REDIRECT generate script ./db2restorep30_13oct.ddl"

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Step2:Once the .ddl file is generated ,copy it in notepad or use vi editor to  make some changes.

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Steps3:Below changes need to be done

Replace all P30 with S30  with exception of these lines (UPDATE COMMAND OPTIONS USING S ON Z ON P30_NODE0000.out V ON , RESTORE DATABASE P30, OPTIONS '@/db2/db2s30/DB2_CFG_P30_restore')

Use  below parameters

OPEN 6 SESSIONS,

DBPATH ON '/db2/S30'

LOGTARGET '/db2/S30/log_dir/NODE0000/'

uncomment taken on and with prompting and Comment last command in file --RESTORE DATABASE S30 CONTINUE;

Step 4:Once the changes are done in file ,execute below command .

db2 -tvf <new file name>-z <output file name>

e.g.

db2 -tvf db2restorep30_13oct_1.ddl -z db2restorep30_13oct_1.out

output:- DB20000I  The SET TABLESPACE CONTAINERS command completed successfully

Then execute second command

----------------------------------------------------------------------

Step5:create a file like this ,if not present on the server

cat restore_p30_continue.sql

-- ** start redirected restore

-- *****************************************************************************

RESTORE DATABASE P30 CONTINUE;

-- *****************************************************************************

-- ** end of file

-- *****************************************************************************

ROLLFORWARD DATABASE S30 TO END OF LOGS AND  COMPLETE;

-- *****************************************************************************

-- ** end of file

-- *****************************************************************************

nohup db2 -tvf restore_p30_continue.sql >restore13oct.out &

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Step6:Monitor the Db2 restore using db2top then u

Once the restore complete then run the below command

db2 rollforward db <database name>  query status

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Step7:

db2 rollforward db S30  query status

Once the output is not pending ,it means restore is successful .

EMC DATA DOMAIN DATA INVULNERABILITY ARCHITECTURE

Data Domain works on this architecture to provide high availability of data in backup.In this architecture main focus is to prevent data corruption.There are various algorithm and process to ensure it.The main goal is to protect Data Domain File system from corruption.
The Data Domain operating system (DD OS) is purpose-built for
data invulnerability. There are four critical areas of focus:

• End-to-end verification-In this process data integrity is maintained.End-to-end verification means reading data after it is written and comparing it to what was sent to disk, proving that it is reachable through the file system to disk, and proving the data has not been corrupted.

• Fault avoidance and containment:Maintain Data Integrity.This is achieved by below steps.

  1-New data never overwrites good data:

  2-Fewer complex data structures:
As long as the system can keep track of the head of the log, new writes will not touch old data. This design simplicity greatly reduces the chances of software errors that could lead to data corruption


  3.NVRAM for fast, safe restart

  4.Persistent RAM protection
Data in RAM is protected by a persistent RAM Implementation (PRAM).Data Domain system move data from RAM to disk in a process called vaulting.


  5.No partial stripe writes:
Data Domain System never update just one block in a stipe.Following no-overrite good data policy,all new writes go to new RAID stripes are written in their entirety.



• Continuous fault detection and healing:

  RAID 6: Double disk failure protection, read error correction:

1. Each shelf include a global spare drive which automatically replace a failed drive ,which automatically replace a failed drive anywhere in Data Domain System.
2. When a hot swappable failed drive is replaced by EMC,it become new global spare.

 On-the-fly error detection and correction:
On the every read from disk the system first verifies that the block read from disk is the block excepted.It then use the checksum to verify integrity.


Scrub to insure data doesn’t go bad
Re-verify the integrity of all data .Scrubbing process intelligently find and repair defect on the disk before they can become a problem.


 

File system recoverability


 File system recoverability:
To re-construct lost or corrupted file system metadata and also file system check tools that can bring an ailing system safely back online quickly.


  
Self-describing data format to ensure metadata recoverability:
All data is stored along with metadata that describes it. If a metadata structure is somehow
corrupted, there are two levels of recoverability. 

1.  A snapshot is kept of the file system metadata every several hours; recoverability can rely on this point-in-time copy. 
2. The data can be scanned on disk and the metadata structure can be rebuilt.
   These capabilities enable recoverability even if there is a worst case corruption of the file system or its metadata.
   
   
   

 FS check, if needed, is fast:
Data Domain file system never overwrites old data and doesn’t have block maps and
reference counts to rebuild, it only has to verify where the head of the log is to safely
bring the system back online to restore critical data.
 ====================================================

EMC Networker Basics Command.

There are few networker commands which should be handy to backup admin.

1)mminfo
2)nsrck
3)nsrmm:a command line interface to manage the media and devices (tapes, disks, and files) used by NetWorker servers and storage nodes.



nsrmm -d : Delete the backup volume named volume_name.

nsrmm -d -P :  Purge the file index entries from both the file index  and the media index for the backup volume named volume_name.

nsrmm -l :Label a backup volume with the name volume_name.
nsrmm -m    Mount the backup volume.
nsrmm -m -l -R     Recycle and mount backup volume.
nsrmm -u  :  Unmount the backup


4)nsrinfo
5)savegrp