On Fri, Aug 25, 2023 at 9:40 AM Marko Mäkelä <[email protected]> wrote:
> Like Gordan has said in this thread, you might just let the file > system handle compression if you need it. But, there is no free lunch. > I suppose that ZFS would not support O_DIRECT. Doesn't support it YET. But if the concern is double-caching things, then ZFS has a solution for that - setting primarycache=metadata. Obviously buffered write require an extra memcopy, so things will get faster when O_DIRECT implementation lands, but this is generally not where significant bottlenecks are at the moment, especially when you can set sync=disabled and still preserve write ordering (which makes it safer than disabling innodb_flush_log_at_trx_commit, sync_binlog, sync_master_info, and similar). > In any case, with file > system compression, page writes would become more than a simple matter > of sending the data to a DMA controller. You could also let the > storage layer handle compression. I was really impressed by the > performance of ScaleFlux when we tested it some years ago. ZFS compression performance is fast enough that it isn't really a problem. In many cases (spinning rust, slower SSDs), it often makes things faster because disk throughput is a bigger bottleneck than the compression cost. _______________________________________________ discuss mailing list -- [email protected] To unsubscribe send an email to [email protected]
