Re: [reiserfs-list] Data loss during power off
Henrique Faria writes: Nikita, I did not find any download link to Reiser4 in the site at all. Thanks, Sorry, I meant 30 Sept. 2002, of course. Or is it 31 Dec. 2002? Anyway, wait a bit. :) Henrique On Thu, 27 Jun 2002 12:01:54 +0400, Nikita Danilov [EMAIL PROTECTED] escreveu : De: Nikita Danilov [EMAIL PROTECTED] Data: Thu, 27 Jun 2002 12:01:54 +0400 Para: Henrique Faria [EMAIL PROTECTED] Assunto: Re: [reiserfs-list] Data loss during power off Henrique Faria writes: Does changing JOURNAL_MAX_TRANS_AGE and JOURNAL_MAX_COMMIT_AGE values make any sense? Well, at least, it seemed to. I read something about Reiser4 APIs to handle transactions, in the reiser FAQs (question 47). Nikita Danilov wrote some words mentioning this feature. I wonder if it could solve my problems. By the way, when reiser4 will be available? See http://www.namesys.com: Reiser4 is due 30 Sept. 2001. Thank you all, Henrique R. Faria On Wed, 26 Jun 2002 09:08:29 +0400, Oleg Drokin [EMAIL PROTECTED] escreveu : De: Oleg Drokin [EMAIL PROTECTED] Data: Wed, 26 Jun 2002 09:08:29 +0400 Para: Henrique Faria [EMAIL PROTECTED] Assunto: Re: [reiserfs-list] Data loss during power off Hello! This (almost) cannot be done. Of course you may resort to opening files with O_SYNC or issuing sync/fsync calls after each write, this way you'd lose even less data by the cost of speed of fs operations. At least with this approach you may be sure that after sync/fsync returned (or write in case of oepning with O_SYNC), data are safe on the media. (This is assuming that your flash memory card does not do any cheating and does not report it have completed command before actual writing). Bye, Oleg On Tue, Jun 25, 2002 at 09:09:04PM +, Henrique Faria wrote: Hello! We're using reiserfs 3.6.25 and linux 2.4.18, in a 256 MB flash memory card, to develop a game. Data is written all the time, in local files, by the main process. The power off test has to be done, for the machines will be turned off with no shutdown process. What's happening: pressing the power off button (during data writing) makes data to be lost. Is it possible to force the data to be written in the file system? I tried to change the JOURNAL_MAX_TRANS_AGE and the JOURNAL_MAX_COMMIT_AGE consts. Less data is lost, but I still get some loss. Thanks, Henrique R. Faria Nikita.
Re: [reiserfs-list] Data loss during power off
Well, changing both JOURNAL_MAX_TRANS_AGE and JOURNAL_MAX_COMMIT_AGE to 0.1 and making the following configuration for flash devices JOURNAL_BLOCK_COUNT 512 JOURNAL_TRANS_MAX 128 JOURNAL_MAX_BATCH 127 I was able to force data flush just after the file write C instructions (with O_SYNC or fsync). I did not get performance problems for while, maybe because it's a linux dedicated for a single game. Thanks everybody, Henrique R. Faria On Thu, 27 Jun 2002 21:58:00 +0400, Nikita Danilov [EMAIL PROTECTED] escreveu : De: Nikita Danilov [EMAIL PROTECTED] Data: Thu, 27 Jun 2002 21:58:00 +0400 Para: Henrique Faria [EMAIL PROTECTED] Assunto: Re: [reiserfs-list] Data loss during power off Henrique Faria writes: Nikita, I did not find any download link to Reiser4 in the site at all. Thanks, Sorry, I meant 30 Sept. 2002, of course. Or is it 31 Dec. 2002? Anyway, wait a bit. :) Henrique On Thu, 27 Jun 2002 12:01:54 +0400, Nikita Danilov [EMAIL PROTECTED] escreveu : De: Nikita Danilov [EMAIL PROTECTED] Data: Thu, 27 Jun 2002 12:01:54 +0400 Para: Henrique Faria [EMAIL PROTECTED] Assunto: Re: [reiserfs-list] Data loss during power off Henrique Faria writes: Does changing JOURNAL_MAX_TRANS_AGE and JOURNAL_MAX_COMMIT_AGE values make any sense? Well, at least, it seemed to. I read something about Reiser4 APIs to handle transactions, in the reiser FAQs (question 47). Nikita Danilov wrote some words mentioning this feature. I wonder if it could solve my problems. By the way, when reiser4 will be available? See http://www.namesys.com: Reiser4 is due 30 Sept. 2001. Thank you all, Henrique R. Faria On Wed, 26 Jun 2002 09:08:29 +0400, Oleg Drokin [EMAIL PROTECTED] escreveu : De: Oleg Drokin [EMAIL PROTECTED] Data: Wed, 26 Jun 2002 09:08:29 +0400 Para: Henrique Faria [EMAIL PROTECTED] Assunto: Re: [reiserfs-list] Data loss during power off Hello! This (almost) cannot be done. Of course you may resort to opening files with O_SYNC or issuing sync/fsync calls after each write, this way you'd lose even less data by the cost of speed of fs operations. At least with this approach you may be sure that after sync/fsync returned (or write in case of oepning with O_SYNC), data are safe on the media. (This is assuming that your flash memory card does not do any cheating and does not report it have completed command before actual writing). Bye, Oleg On Tue, Jun 25, 2002 at 09:09:04PM +, Henrique Faria wrote: Hello! We're using reiserfs 3.6.25 and linux 2.4.18, in a 256 MB flash memory card, to develop a game. Data is written all the time, in local files, by the main process. The power off test has to be done, for the machines will be turned off with no shutdown process. What's happening: pressing the power off button (during data writing) makes data to be lost. Is it possible to force the data to be written in the file system? I tried to change the JOURNAL_MAX_TRANS_AGE and the JOURNAL_MAX_COMMIT_AGE consts. Less data is lost, but I still get some loss. Thanks, Henrique R. Faria Nikita.
Re: [reiserfs-list] Data loss during power off
On Tue, 2002-06-25 at 17:09, Henrique Faria wrote: Hello! We're using reiserfs 3.6.25 and linux 2.4.18, in a 256 MB flash memory card, to develop a game. Data is written all the time, in local files, by the main process. The power off test has to be done, for the machines will be turned off with no shutdown process. What's happening: pressing the power off button (during data writing) makes data to be lost. Is it possible to force the data to be written in the file system? I tried to change the JOURNAL_MAX_TRANS_AGE and the JOURNAL_MAX_COMMIT_AGE consts. Less data is lost, but I still get some loss. Thanks, The data logging patches also include data=ordered mode. Using that, plus setting the max trans age (or max batch count), will flush data blocks right away. I'm waiting for a tester to confirm I've fixed the page locking problem w/writepage in the current data logging patch, then I'll do a new release. -chris
Re: [reiserfs-list] Data loss during power off
On Thu, 2002-06-27 at 08:36, Henrique Faria wrote: I'll try the patch! Can JOURNAL_MAX_TRANS_AGE be zero? Do I need to set up JOURNAL_MAX_COMMIT_AGE too? No, the best way to do it is to set JOURNAL_MAX_BATCH to 1. That way it is size dependent instead of age dependent. The namesys journal relocation patch (which my data logging stuff is against), includes the ability to set these parameters on a per FS basis without recompiling. -chris
Re: [reiserfs-list] Data loss during power off
On Thu, 2002-06-27 at 11:34, Henrique Faria wrote: Well, changing both JOURNAL_MAX_TRANS_AGE and JOURNAL_MAX_COMMIT_AGE to 0.1 and making the following configuration for flash devices JOURNAL_BLOCK_COUNT 512 JOURNAL_TRANS_MAX 128 JOURNAL_MAX_BATCH 127 I was able to force data flush just after the file write C instructions (with O_SYNC or fsync). I did not get performance problems for while, maybe because it's a linux dedicated for a single game. All of the journal parameters should be ints. Setting them to 0.1 won't have quite the desired effect. If you have JOURNAL_MAX_BATCH set to 1, you can ignore JOURNAL.*AGE, and the transaction will commit after each write. -chris
