Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
Ann, thanks for the correction. I erroneously missinterpreted that file system barriers were also necessary. Aldo ++ Visit http://www.firebirdsql.org

RE: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support]
> I run 2.5.2 on a virtual Server 2008R2 machine. > Is FW on by default on this install? FW is not a function of the install or server config, it is a database property that is determined by the OS which was used to create the database*. For all version of Windows the default = ON I am not su

Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread Ann Harrison aharri...@ibphoenix.com [firebird-support]
On Aug 20, 2014, at 9:05 AM, "Aldo Caruso aldo.car...@argencasas.com [firebird-support]" wrote: >> The hard truth is that the only _absolute guarantee_ to prevent > database corruption is FW = ON. > > Provided that the file system also has barrier enabled ... Firebird's forced write should be

Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread 'E. D. Epperson Jr' dixonepper...@gmail.com [firebird-support]
Thanks for the tip. I did take the default install and yes, FW is on. On Wed, Aug 20, 2014 at 10:08 AM, Aldo Caruso aldo.car...@argencasas.com [firebird-support] wrote: > > > You can check whether forced writes status is on or off submitting on a > FB console the following command > > SHOW DAT

Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
You can check whether forced writes status is on or off submitting on a FB console the following command SHOW DATABASE In order to set it on / off, you shoud run gfix -user [user_name] -password [psw] -w [sync | async] [database_name] Regards, Aldo

Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread 'E. D. Epperson Jr' dixonepper...@gmail.com [firebird-support]
I've a question regarding this, since the context has been in Linux. I run 2.5.2 on a virtual Server 2008R2 machine. Is FW on by default on this install? If not, is that a setting in the conf file or do I need to use GFix On Wed, Aug 20, 2014 at 9:05 AM, Aldo Caruso aldo.car...@argencasas.com [f

Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
> The hard truth is that the only _absolute guarantee_ to prevent database corruption is FW = ON. Provided that the file system also has barrier enabled ... Regards, Aldo ++

Re: {Disarmed} Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread 'Carlos H. Cantu' lis...@warmboot.com.br [firebird-support]
www.FireBase.com.br EHehdfs> Am 19.08.2014 um 18:30 schrieb 'Carlos H. Cantu' lis...@warmboot.com.br EHehdfs> [firebird-support]: >> Re: [firebird-support] Forced write, page size and buffer size The >> best thing would be if someone could simulate some crashes (like power &g

Re: {Disarmed} Re: [firebird-support] Forced write, page size and buffer size

2014-08-20 Thread Elmar Haneke el...@haneke.de [firebird-support]
Am 19.08.2014 um 18:30 schrieb 'Carlos H. Cantu' lis...@warmboot.com.br [firebird-support]: > Re: [firebird-support] Forced write, page size and buffer size The > best thing would be if someone could simulate some crashes (like power > failure) in both configurations an

RE: [firebird-support] Forced write, page size and buffer size

2014-08-19 Thread 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support]
> Afair, in previous talks, Ann suggested that if you have to choose one or > another, choose FW ON. > > The best thing would be if someone could simulate some crashes (like power > failure) in both configurations and report back about existence of corruption. Unfortunately, it is not always pos

Re: [firebird-support] Forced write, page size and buffer size

2014-08-19 Thread 'Carlos H. Cantu' lis...@warmboot.com.br [firebird-support]

Re: [firebird-support] Forced write, page size and buffer size

2014-08-19 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
Carlos, I agree with you. The performance degradation was very high on an ext4 file system ( which has barrier enabled by default ). On the other hand, I found no noticiable performance degradation on an ext3 file system ( which has barrier disabled by default ). Having barrier disab

Re: [firebird-support] Forced write, page size and buffer size

2014-08-19 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
Rich, I got the point: with forced writes off you can't be sure of when the data is sent to disk. But, in that case, what is the point of turning it off ? If you must wait for the server shut down to be 100% sure that the data is written to disk, isn't the risk too high to have forced write of

Re: [firebird-support] Forced write, page size and buffer size

2014-08-19 Thread Aldo Caruso aldo.car...@argencasas.com [firebird-support]
Sean, thanks for your answer. Aldo El 18/08/14 a las 15:59, 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support] escibiĆ³: > Given this scenario my questions are the following: > > 1) Does it makes sense to activate forced writes on Linux ? Different versions of Linux file systems

Re: [firebird-support] Forced write, page size and buffer size

2014-08-18 Thread 'Carlos H. Cantu' lis...@warmboot.com.br [firebird-support]
Usually, if you turn FW = ON on Linux, and your filesystem has barrier enabled, it will affect performance of batch updates really badly. You would either accept the performance degradation, or disable one of them (FW or barrier). Carlos Firebird Performance in Detail - http://videos.firebirddeve

Re: [firebird-support] Forced write, page size and buffer size

2014-08-18 Thread 'Saunders, Rich' greym...@mykolab.com [firebird-support]
On 2014-08-18 14:51, Aldo Caruso aldo.car...@argencasas.com [firebird-support] wrote: >After that I noticed that some massive updates ( 100K records ) took > nearly 5 minutes, whereas with async writes it used to take 10 seconds. Of course, we don't know how much work actually took place duri

RE: [firebird-support] Forced write, page size and buffer size

2014-08-18 Thread 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support]
>Given this scenario my questions are the following: > > 1) Does it makes sense to activate forced writes on Linux ? Different versions of Linux file systems provide better protection than others. Personally, I believe that forced write = ON is necessary for all OS -- but I suspect that I