DOAG Conference Fast Backup & Restore using Multisection November Nürnberg. Sinan Petrus Toma

Transcription

1 DOAG Conference November Nürnberg Fast Backup & Restore using Multisection Sinan Petrus Toma

2 About me Sinan Petrus Toma Oracle Database Administrator Page

3 Finanz Informatik GmbH & Co. KG IT Service Provider for Sparkassen-Finanzgruppe 393 Sparkassen, 8 Landesbanken, 8 Landesbausparkassen, DekaBank, IT Services: Application Development Infrastructure and Computer Center Operating Consulting, Training, and Support Based in Frankfurt a.m., Hannover, and Münster Employees: ~ Oracle Databases: ~ All systems: ~ 300M transactions per day Page

4 Agenda Multisection Backup Backup Configurations Examples Backup & Restore Multiplexed Backup Section Size Considerations Further Backup Improvements Multisection VALIDATE Multisection Performance Data Duplexed Backup Summary Page

5 Multisection Backup Divide large datafiles into sections can be backed up in parallel File section: continuous range of blocks in a datafile SECTION SIZE keyword in BACKUP command datafile section 1 session 1 backup set 1 section 2 session 2 backup set 2 section 3 session 3 backup set 3 section 4 session 4 backup set 4 Page

6 Multisection Backup Prior to Oracle 11g Lowest unit of RMAN parallelism was datafile Could not backup single large datafile in parallel From Oracle 11g multisection backups for: Full backups using backup sets Incremental level 0 backups using backup sets From Oracle 12c multisection backups for: Full backups using backup sets or image copies Incremental level 0 backups using backup sets or image copies Incremental level 1 backups (using backup sets) Page

7 Backup Configurations Option Default Description PARALLELISM 1 Number of processes work in parallel MAXOPENFILES 8 FILESPERSET 64 Number of files can be read simultaneously by each channel Maximum number of files in each backup set MAXPIECESIZE unlimited Maximum size of a backup piece SECTION SIZE not defined Maximum size of a file section Page

8 Example 1: PARALLELISM = 4 Option Default Example 1 PARALLELISM 1 4 MAXOPENFILES 8 8 FILESPERSET MAXPIECESIZE unlimited unlimited SECTION SIZE not defined not defined run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk; ALLOCATE CHANNEL ch2 DEVICE TYPE disk; ALLOCATE CHANNEL ch3 DEVICE TYPE disk; ALLOCATE CHANNEL ch4 DEVICE TYPE disk; BACKUP DATABASE TAG backup01; } 17 datafiles #1 = 666M Page

9 Example 1: Backup Metadata SELECT s.recid, s.pieces, p.piece#, p.handle, s.multi_section, count(d.file#) count_df FROM v$backup_set s JOIN v$backup_piece p ON (p.recid = s.recid) JOIN v$backup_datafile d ON (d.set_stamp = p.set_stamp AND d.set_count = p.set_count) WHERE p.tag = 'BACKUP01' GROUP BY s.recid, s.pieces, p.piece#, p.handle, s.multi_section, p.compressed ORDER BY s.recid, p.piece#; Page

10 Example 1: Backup Metadata Details SELECT s.recid, s.pieces, p.piece#, p.handle, s.multi_section, d.file# FROM v$backup_set s JOIN v$backup_piece p ON (p.recid = s.recid) JOIN v$backup_datafile d ON (d.set_stamp = p.set_stamp AND d.set_count = p.set_count) WHERE p.tag = 'BACKUP01' ORDER BY s.recid, p.piece#, d.file#; Page

11 Example 1: Restore run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk; ALLOCATE CHANNEL ch2 DEVICE TYPE disk; ALLOCATE CHANNEL ch3 DEVICE TYPE disk; ALLOCATE CHANNEL ch4 DEVICE TYPE disk; SET NEWNAME FOR DATAFILE 1 TO '/tmp/restore01.dbf'; RESTORE DATAFILE 1 FROM TAG = 'BACKUP01'; } Page

12 Example 1: Multiplexed Backup Sets datafile 1 datafile 2 datafile 3 session 1 backup set datafile 4 backup set 1 n datafile Page

13 Multiplexed Backup Backup set contains multiple datafiles Only whole files, never partial files, are included in a backup set RMAN simultaneously reads multiple files from disk and writes their blocks into the same backup set Image copies can never be multiplexed Level of Multiplexing = min(filesperset, min(maxopenfiles, files_per_channel)) Disadvantages Restore a datafile must read complete backup set and search for datafile blocks Only one session per datafile Page

14 Example 2: MAXOPENFILES = 1 Option Default Example 1 PARALLELISM 1 4 MAXOPENFILES 8 1 FILESPERSET MAXPIECESIZE unlimited unlimited SECTION SIZE not defined not defined run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch2 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch3 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch4 DEVICE TYPE disk MAXOPENFILES = 1; BACKUP DATABASE TAG backup02; } Page

15 Example 2: Backup Metadata Page

16 Example 2: MAXOPENFILES = 1 datafile 1 datafile 2 session 1 backup set backup set 1 n datafile Page

17 Example 2: MAXOPENFILES = 1 Distribution inside the backup set changed 2 files per set instead of 6 or 8 MAXOPENFILES = 1 Session will read one datafile at a time Session will write the backup data into the backup piece sequentially FILESPERSET still > 1 MAXPIECESIZE set to default (=unlimited) backup set is usually stored in 1 backup piece = FILESPERPIECE Page

18 Example 3: FILESPERSET = 1 Option Default Example 1 PARALLELISM 1 4 MAXOPENFILES 8 1 FILESPERSET 64 1 MAXPIECESIZE unlimited unlimited SECTION SIZE not defined not defined run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch2 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch3 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch4 DEVICE TYPE disk MAXOPENFILES = 1; BACKUP DATABASE FILESPERSET = 1 TAG backup03; } Page

19 Example 3: Backup Metadata Page

20 Example 3: FILESPERSET = 1 backup set 1 datafile 1 session datafile 2 session 2 backup set backup set 1 1 datafile Page

21 Example 4: MAXPIECESIZE = 200M Option Default Example 1 PARALLELISM 1 4 MAXOPENFILES 8 1 FILESPERSET 64 1 MAXPIECESIZE unlimited 200M SECTION SIZE not defined not defined run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk MAXOPENFILES = 1 MAXPIECESIZE = 200M; ALLOCATE CHANNEL ch2 DEVICE TYPE disk MAXOPENFILES = 1 MAXPIECESIZE = 200M; ALLOCATE CHANNEL ch3 DEVICE TYPE disk MAXOPENFILES = 1 MAXPIECESIZE = 200M; ALLOCATE CHANNEL ch4 DEVICE TYPE disk MAXOPENFILES = 1 MAXPIECESIZE = 200M; BACKUP DATABASE FILESPERSET = 1 TAG backup04; } Page

22 Example 4: RMAN Output Page

23 Example 4: Backup Metadata Page

24 Example 4: MAXPIECESIZE = 200M backup set backup set datafile 1 session 1 backup set backup set backup set n 1 datafile Page

25 Example 4: Restore run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk; ALLOCATE CHANNEL ch2 DEVICE TYPE disk; ALLOCATE CHANNEL ch3 DEVICE TYPE disk; ALLOCATE CHANNEL ch4 DEVICE TYPE disk; SET NEWNAME FOR DATAFILE 1 TO '/tmp/restore01.dbf'; RESTORE DATAFILE 1 FROM TAG = 'BACKUP04'; } Page

26 Example 5: SECTION SIZE = 200M Option Default Example 1 PARALLELISM 1 4 MAXOPENFILES 8 1 FILESPERSET 64 1 MAXPIECESIZE unlimited unlimited SECTION SIZE not defined 200M run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch2 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch3 DEVICE TYPE disk MAXOPENFILES = 1; ALLOCATE CHANNEL ch4 DEVICE TYPE disk MAXOPENFILES = 1; BACKUP DATABASE FILESPERSET = 1 SECTION SIZE = 200M TAG backup05; } Page

27 Example 5: RMAN Output (25600*8)/1024 = 200M (( )*8)/1024 = 66MB Page

28 Example 5: Backup Metadata Page

29 Example 5: SECTION SIZE = 200M datafile section 1 section 2 section 3 section 4 session 1 session 2 session 3 session 4 backup set backup set backup set backup set backup set n 1 datafile Page

30 Example 5: Restore Command run { ALLOCATE CHANNEL ch1 DEVICE TYPE disk; ALLOCATE CHANNEL ch2 DEVICE TYPE disk; ALLOCATE CHANNEL ch3 DEVICE TYPE disk; ALLOCATE CHANNEL ch4 DEVICE TYPE disk; SET NEWNAME FOR DATAFILE 1 TO '/tmp/restore01.dbf'; RESTORE DATAFILE 1 FROM TAG = 'BACKUP05'; } Page

31 Example 5: Restore Output Page

32 Multisection AS COPY FILESPERSET option cannot be used with AS COPY: RMAN run { BACKUP AS COPY DATAFILE 1 SECTION SIZE = 200M TAG backup06; } Page

33 Multisection AS COPY SELECT file#, name FROM v$datafile_copy WHERE tag = 'BACKUP06'; Restore by only ONE channel!!! Copy on disk no restore needed Use SWITCH DATAFILE TO COPY Page

34 Multisection Further Information SECTION SIZE and MAXPIECESIZE mutually exclusive FILESPERSET > 1 + SECTION SIZE FILESPERSET = 1 Multisection always with FILESPERSET = 1 Up to 256 Sections per datafile Section size > file size RMAN does not use multisection for that file Section size to small and produces > 256 sections RMAN increases the section size to a value that results in exactly 256 sections Page

35 Multisection Further Information Backup of datafile not completed successfully Possible to get records in the repository of partial backup set RMAN does not consider partial backups for restore & recovery Backup not restartable Fails after section 1 and 2 has to be backed up again must use DELETE command to delete the records Non-multisection Record in repository only if backup completes successfully Can only be used to backup the datafiles Cannot use this option to backup the control file Page

36 Section Size Considerations Choose section size depending on Datafile size Degree of parallelism Datafile size = 32G / 8 Channels Section Size = 4G Possible to choose different section sizes for different files Back up files separately Develop own backup strategy Page

37 Section Size Considerations (Huge) increase of number of backup sets Can your device or tape manager handle this? Parallelism More I/O and CPU usage Only Enterprise Edition Page

38 Further Backup Improvements BACKUP_TAPE_IO_SLAVES = false RMAN allocates tape buffers from PGA BACKUP_TAPE_IO_SLAVES = true RMAN allocates tape buffers from SGA (Large Pool) Large Pool not specified from Shared Pool Shared Pool too small from PGA Advanced Compression Option Medium Otherwise Basic Page

39 Multisection VALIDATE Check for corrupt blocks and missing files Determine whether a backup set can be restored [BACKUP] VALIDATE [CHECK LOGICAL] SECTION SIZE 2G DATABASE; VALIDATE can check individual backup sets and data blocks BACKUP VALIDATE not Page

40 Multisection VALIDATE VALIDATE CHECK LOGICAL SECTION SIZE 200M DATAFILE 1; Page

41 Multisection Backup Performance Data Backup Database DB Size Config E1 Config E5 Time % 55G 00:10 00:08 80% 265G 01:41 01:30 89% Backup Datafile: Section Size = 2G DB Size Config E1 Config E5 Time % 100G (Bigfile) 00:39 00:14 36% Option E1 E5 PARALLELISM 4 4 MAXOPENFILES 8 1 FILESPERSET 64 1 MAXPIECESIZE unl. unl. SECTION SIZE - 200M Page

42 Multisection Restore Performance Data Restore Database DB Size Config E1 Config E5 Time % 55G 00:29 00:17 59% 265G 02:41 02:06 78% Restore Datafile: Section Size = 2G File Size Config E1 Config E5 Time % 8G 00:08 00:03 38% 16G 00:24 00:06 25% 32G 01:01 00:12 20% 32G (system load) 100G (Bigfile) 03:29 00:50 24% 00:34 00:12 35% Page

43 Duplexed Backup Sets Make multiple backups of the same backup set simultaneously when backing up datafiles, control file, archived redo logs, or server parameter file Up to four duplexed copies of each backup piece, to disk OR tape Not to disk AND tape simultaneously Cannot duplex image copies only backup sets run { BACKUP AS BACKUPSET COPIES 3 FORMAT /u01/copy_1_%u, /u02/copy_2_%u, /u03/copy_3_%u [SECTION SIZE = 200M] DATABASE; } Page

44 Duplexed Multiplexed Backup Sets datafile 1 datafile 2 datafile 3 datafile 4 session 1 backup set Page

45 Duplexed Multisection Backup Sets datafile section 1 session backup set 1 section 2 session backup set 2 section 3 session backup set 3 section 4 session backup set 4 Page

46 Summary Option E1 E2 E3 E4 E5 PARALLELISM MAXOPENFILES FILESPERSET MAXPIECESIZE unlimited unlimited unlimited 200M unlimited SECTION SIZE M Set : Datafile 1:n 1:n 1:1 n:1 n:1 Restore Parallelism Thank you for your kind attention Page