Re: [DOCS] [HACKERS] Online backup vs Continuous backup
Tom Lane wrote: > Bruce Momjian writes: > >> This addresses the technical workings of the various backup systems. > >> The fact that it is or isn't on-line, hot, continuous, fast, or flexible > >> is secondary. > > > To me, the continuous activity is the significant feature of that backup > > method. I chose "Continuous Backup" because it is the continual > > activity that is significant. "Continuous Archiving"? > > I like Peter's suggestion as-is; or "WAL Archiving". I don't like > applying adjectives that are not specific to the particular method. > That will just create more confusion down the road if we add another > feature that could also be called "continuous archiving". I do like "WAL Archiving" but I am concerned that it references a specific internal implementation detail (WAL). Is that OK? Also, I am concerned that is specificially talks about archiving the wal files and is not general enough to include the file system backup that is also necessary. -- Bruce Momjian http://candle.pha.pa.us SRA OSS, Inc. http://www.sraoss.com + If your life is a hard drive, Christ can be your backup. + ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [HACKERS] Online backup vs Continuous backup
"Andrew Dunstan" <[EMAIL PROTECTED]> writes: > Greg Stark said: > > Well fwiw what pg_dump does isn't even considered a "backup" at all in > > other systems. It's a "logical export" or something of that sort. > > > > It's not considered a "backup" because it's saving something different > > than the actual physical database. When you restore you get something > > (hopefully) logically equivalent but still physically different. > > This seems fairly arbitrary. On that basis anything on a higher level than > dd is not a backup method, ISTM. Well most of other options *aren't* any higher level than dd. Even with PITR you're just storing the transaction logs byte for byte. When you replay it works at slightly higher level but it's still far from reinterpreting your data and you'll get (almost) exactly the same bytes back. I'm not saying pg_dump is a bad thing, but now that Postgres has real backups there isn't much of a use case for using pg_dump as a stand-in for backups. If your system crashes and you need to bring up a new system quickly you want to bring it up in exactly the state the one that crashed was in. You don't want to pass all the data through a program that interprets the ascii representation again and hope it comes up with the same data. There are other reasons to need pg_dump of course. Just not for backups. -- greg ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [HACKERS] Online backup vs Continuous backup
Greg Stark said: > Bruce Momjian writes: > >> I noticed that we are using the term "Online Backup" in our >> documentation when we are talking about continuous backup and PITR. >> >> To me, "online backup" is doing a backup while the system is online >> (online-backup), and that is accomplished by pg_dump. > > Well fwiw what pg_dump does isn't even considered a "backup" at all in > other systems. It's a "logical export" or something of that sort. > > It's not considered a "backup" because it's saving something different > than the actual physical database. When you restore you get something > (hopefully) logically equivalent but still physically different. This seems fairly arbitrary. On that basis anything on a higher level than dd is not a backup method, ISTM. cheers andrew ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [DOCS] [HACKERS] Online backup vs Continuous backup
Bruce Momjian writes: >> This addresses the technical workings of the various backup systems. >> The fact that it is or isn't on-line, hot, continuous, fast, or flexible >> is secondary. > To me, the continuous activity is the significant feature of that backup > method. I chose "Continuous Backup" because it is the continual > activity that is significant. "Continuous Archiving"? I like Peter's suggestion as-is; or "WAL Archiving". I don't like applying adjectives that are not specific to the particular method. That will just create more confusion down the road if we add another feature that could also be called "continuous archiving". regards, tom lane ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] Online backup vs Continuous backup
Bruce Momjian writes: > I noticed that we are using the term "Online Backup" in our > documentation when we are talking about continuous backup and PITR. > > To me, "online backup" is doing a backup while the system is online > (online-backup), and that is accomplished by pg_dump. Well fwiw what pg_dump does isn't even considered a "backup" at all in other systems. It's a "logical export" or something of that sort. It's not considered a "backup" because it's saving something different than the actual physical database. When you restore you get something (hopefully) logically equivalent but still physically different. Hot backups which is what you read "online backup" to mean is pretty closely tied to PITR log archiving backups. One isn't very useful without the other. Specifically, you can have all the archived logs in the world but if you don't have a backup to start from they're useless. And in postgres I gather hot backups aren't very useful if you don't have the transaction logs necessary to fix any torn pages. -- greg ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [DOCS] [HACKERS] Online backup vs Continuous backup
Peter Eisentraut wrote: > Am Montag, 26. Dezember 2005 20:46 schrieb Heikki Linnakangas: > > FWIW, I believe "log archival" is a common term for that. > > I like that better, although there are a lot of logs, so maybe > "transaction log archival". Yep, when I think of log archiving, I think of saving the server logs, which thanks to log file rotation, we kind of support. The problem is that when I think of the transaction log, I think of clog because it is the transaction status log. :-( I am thinking anything that says "log" is going to be confusing. How about "Transaction Archiving"? > Considering the list originally referenced: > > - File system backup - SQL dump - (Transaction log archival?) > > This addresses the technical workings of the various backup systems. > The fact that it is or isn't on-line, hot, continuous, fast, or flexible > is secondary. To me, the continuous activity is the significant feature of that backup method. I chose "Continuous Backup" because it is the continual activity that is significant. "Continuous Archiving"? -- Bruce Momjian| http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup.| Newtown Square, Pennsylvania 19073 ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [DOCS] [HACKERS] Online backup vs Continuous backup
Am Montag, 26. Dezember 2005 20:46 schrieb Heikki Linnakangas: > FWIW, I believe "log archival" is a common term for that. I like that better, although there are a lot of logs, so maybe "transaction log archival". Considering the list originally referenced: - File system backup - SQL dump - (Transaction log archival?) This addresses the technical workings of the various backup systems. The fact that it is or isn't on-line, hot, continuous, fast, or flexible is secondary. ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [DOCS] [HACKERS] Online backup vs Continuous backup
On Mon, 26 Dec 2005, Bruce Momjian wrote: Joshua D. Drake wrote: I have never heard the term Continuous backup. Although I have heard online backup. The problem is that when I hear the term online backup I think Hot backup which is what we do with pg_dump. Yes, that is my problem too. I would just call the other Point in time recovery :) The problem there is that it is "recovery", and the documentation talks about the "backup" step. I am thinking we are going to have to add something like "Continuous backup, also called Online Backup" or something like that. FWIW, I believe "log archival" is a common term for that. - Heikki ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [DOCS] [HACKERS] Online backup vs Continuous backup
Joshua D. Drake wrote: > Bruce Momjian wrote: > > I noticed that we are using the term "Online Backup" in our > > documentation when we are talking about continuous backup and PITR. > > > > To me, "online backup" is doing a backup while the system is online > > (online-backup), and that is accomplished by pg_dump. I know a lot of > > databases us "Online Backup" but I assume this is for historical reasons > > because at some time in the past their full backups didn't work while > > the database was online. Other systems use the term "Continuous > > Logging", but I think that is too easily confused with the server > > activity logs. > > > > I suggest the following patch to rename our capability "Continuous > > Backup". > > I have never heard the term Continuous backup. Although I have heard > online backup. The problem is that when I hear the term online backup > I think Hot backup which is what we do with pg_dump. Yes, that is my problem too. > I would just call the other Point in time recovery :) The problem there is that it is "recovery", and the documentation talks about the "backup" step. I am thinking we are going to have to add something like "Continuous backup, also called Online Backup" or something like that. -- Bruce Momjian| http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup.| Newtown Square, Pennsylvania 19073 ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] Online backup vs Continuous backup
Bruce Momjian wrote: I noticed that we are using the term "Online Backup" in our documentation when we are talking about continuous backup and PITR. To me, "online backup" is doing a backup while the system is online (online-backup), and that is accomplished by pg_dump. I know a lot of databases us "Online Backup" but I assume this is for historical reasons because at some time in the past their full backups didn't work while the database was online. Other systems use the term "Continuous Logging", but I think that is too easily confused with the server activity logs. I suggest the following patch to rename our capability "Continuous Backup". I have never heard the term Continuous backup. Although I have heard online backup. The problem is that when I hear the term online backup I think Hot backup which is what we do with pg_dump. I would just call the other Point in time recovery :) ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
[HACKERS] Online backup vs Continuous backup
I noticed that we are using the term "Online Backup" in our documentation when we are talking about continuous backup and PITR. To me, "online backup" is doing a backup while the system is online (online-backup), and that is accomplished by pg_dump. I know a lot of databases us "Online Backup" but I assume this is for historical reasons because at some time in the past their full backups didn't work while the database was online. Other systems use the term "Continuous Logging", but I think that is too easily confused with the server activity logs. I suggest the following patch to rename our capability "Continuous Backup". -- Bruce Momjian| http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup.| Newtown Square, Pennsylvania 19073 Index: backup.sgml === RCS file: /cvsroot/pgsql/doc/src/sgml/backup.sgml,v retrieving revision 2.76 diff -c -r2.76 backup.sgml *** backup.sgml 7 Nov 2005 17:36:44 - 2.76 --- backup.sgml 26 Dec 2005 16:30:48 - *** *** 19,25 SQL dump File system level backup !On-line backup Each has its own strengths and weaknesses. --- 19,25 SQL dump File system level backup !Continuous backup Each has its own strengths and weaknesses. *** *** 373,382 ! On-line backup and point-in-time recovery (PITR) !on-line backup --- 373,382 ! Continuous backup and point-in-time recovery (PITR) !continuous backup *** *** 452,458 !To recover successfully using an on-line backup, you need a continuous sequence of archived WAL files that extends back at least as far as the start time of your backup. So to get started, you should set up and test your procedure for archiving WAL files before you take your --- 452,458 !To recover successfully using a continuous backup, you need a continuous sequence of archived WAL files that extends back at least as far as the start time of your backup. So to get started, you should set up and test your procedure for archiving WAL files before you take your *** *** 782,793 pg_start_backup or pg_stop_backup, and you will therefore be left to your own devices to keep track of which backup dump is which and how far back the associated WAL files go. ! It is generally better to follow the on-line backup procedure above. !Recovering with an On-line Backup Okay, the worst has happened and you need to recover from your backup. --- 782,793 pg_start_backup or pg_stop_backup, and you will therefore be left to your own devices to keep track of which backup dump is which and how far back the associated WAL files go. ! It is generally better to follow the continuous backup procedure above. !Recovering with a Continuous Backup Okay, the worst has happened and you need to recover from your backup. *** *** 1123,1129 Caveats ! At this writing, there are several limitations of the on-line backup technique. These will probably be fixed in future releases: --- 1123,1129 Caveats ! At this writing, there are several limitations of the continuous backup technique. These will probably be fixed in future releases: ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
