> It would probably be better to set: > > lctl conf_param fsname-OST00XX.ost.readcache_max_filesize=32M > > or similar, to limit the read cache to files 32MB in size or less (or > whatever you consider "small" files at your site. That allows the read cache > for config files and such, while not thrashing the cache while accessing > large files. > > We should probably change this to be the default, but at the time the read > cache was introduced, we didn't know what should be considered a small vs. > large file, and the amount of RAM and number of OSTs on an OSS, and the uses > varies so much that it is difficult to pick a single correct value for this. I was looking through the Linux vm settings and saw vfs_cache_pressure - has anyone tested performance with this parameter? Do you know if this would this have any effect on file caching vs. ext4 metadata caching?
For us, Linux/Lustre would ideally push out data before the metadata, as the performance penalty for doing 4k reads on the s2a far outweighs any benefits of data caching. Thanks, Kit _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
