Log space
Hi, Is there any "rule of thumb" that would give me an idea how much logical log space we need? In the Administrator's quide their give a following formula: TOTAL LOGSPACE = (users * maxrows) * 512 Is this working? What does the "maxrows" mean? I know there are several factors that have affect on setting logical log parameters, but I would only need some hints to get started. We have a 400 MG database with relatively little update activity. Logical logs are backed up. Thank you very much in advance. Recards Leena Sent via Deja.com http://www.deja.com/ Before you buy.
There are lots of rules of thumb, and they don't all agree. There are two rules of thumb that I tend to adhere to: 1. Figure out how many logs your largest transaction would take up, and multiply by 2.5 (for example, if your largest transaction takes 20MB of log space, then you should have at least 50 MB of logical logs). 2. Have enough logical logs so that you don't reuse any log files in a 24-hour period. So if you chew through an average of 40 logs per day, be sure you have more than 40 log files. Whichever of these two rules results in more log files is the one you should use. Hope this helps, - Tom Girsch <lena_peltonen@my-deja.com> wrote in message news:820rrv$jc0$1@nnrp1.deja.com... > Hi, > > Is there any "rule of thumb" that would give me an idea > how much logical log space we need? In the Administrator's > quide their give a following formula: > > TOTAL LOGSPACE = (users * maxrows) * 512 > > Is this working? What does the "maxrows" mean? > > I know there are several factors that have affect on > setting logical log parameters, but I would only need > some hints to get started. > > We have a 400 MG database with > relatively little update activity. Logical logs are > backed up. > > Thank you very much in advance. > > Recards > > Leena > > > > > > > > > > > > > > Sent via Deja.com http://www.deja.com/ > Before you buy.
Lena, Max rows in this case is going to be the maximum number of rows in your largest update or insert query. The number of users is only the number doing updates and inserts, so if some do none then don't worry about them. So a good start is to probably use the formula but then watch your instance carefully during high load or simulated high load and see how if the backups are keeping up with the activity - if not increase the number of logs. However don't take them too high in number (keep them less than 100) as you can get situations where performance is affected by the way they are managed on disk (I can't remember the specifics, sorry). It is really a balance between the number of logs and the size of logs, and the balance is found through getting a feel for your particular system. HTH ben lena_peltonen@my-deja.com wrote: > Hi, > > Is there any "rule of thumb" that would give me an idea > how much logical log space we need? In the Administrator's > quide their give a following formula: > > TOTAL LOGSPACE = (users * maxrows) * 512 > > Is this working? What does the "maxrows" mean? > > I know there are several factors that have affect on > setting logical log parameters, but I would only need > some hints to get started. > > We have a 400 MG database with > relatively little update activity. Logical logs are > backed up. > > Thank you very much in advance. > > Recards > > Leena > > Sent via Deja.com http://www.deja.com/ > Before you buy.