On Feb 25, 2021, at 9:06 PM, harshad shirwadkar <harshadshirwadkar@xxxxxxxxx> wrote: > > Hi Andreas, > > On Thu, Feb 25, 2021 at 7:43 PM Andreas Dilger <adilger@xxxxxxxxx> wrote: >> >> Yes, modulo using the existing "mb_min_to_scan" parameter for this. >> I think 4 or 8 or 10 groups is reasonable (512MB, 1GB, 1.25GB), >> since if it needs a seek anyway then we may as well find a good >> group for this. > If I understand it right, the meaning of mb_min_to_scan is the number > of *extents* that the allocator should try to find before choosing the > best one. However, what we want here is the number of *groups* that > the allocator should travel linearly before trying to optimize the > search. So, even if mb_min_to_scan is set to 1, by the current > definition of it, it means that the allocator may still traverse the > entire file system if it doesn't find a match. Is my understanding > right? Sorry, you are right. It is the number of extents to scan and not the number of groups. Cheers, Andreas
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