On Wed, Nov 1, 2017 at 4:34 AM, Marat Khalili <mkh@xxxxxx> wrote: >> We do experience severe performance problems now, especially with >> Firefox. Part of my experiment is to reduce the number of snapshots on >> the live volumes, hence this question. > > Just for statistics, how many snapshots do you have and how often do you > take them? It's on SSD, right? I don't think the severe performance problems stem solely from the number of snapshots. I think it is also related to Firefox stuff (cache fragmentation, lack of multi-processor mode maybe, etc.) I still have to investigate the Firefox issues, but I'm starting at the foundation by trying to get a basic BTRFS setup that will support better desktop application performance first. The poor performance has existed from the beginning of using BTRFS + KDE + Firefox (almost 2 years ago), at a point when very few snapshots had yet been created. A comparison system running similar hardware as well as KDE + Firefox (and LVM + EXT4) did not have the performance problems. The difference has been consistent and significant. For a while I thought the difference was due to the hardware, as one system used the z170 chipset and the other used the X99 chipset (but were otherwise equivalent). So I repeated the testing on identical hardware and the stark performance difference remained. When I realized that, I began focusing on BTRFS, as it is the only consistent difference I can recognize. Sometimes I have used Snapper settings like this: TIMELINE_MIN_AGE="1800" TIMELINE_LIMIT_HOURLY="36" TIMELINE_LIMIT_DAILY="30" TIMELINE_LIMIT_MONTHLY="12" TIMELINE_LIMIT_YEARLY="10" However, I also have some computers set like this: TIMELINE_MIN_AGE="1800" TIMELINE_LIMIT_HOURLY="10" TIMELINE_LIMIT_DAILY="10" TIMELINE_LIMIT_WEEKLY="0" TIMELINE_LIMIT_MONTHLY="0" TIMELINE_LIMIT_YEARLY="0" > BTW beware of deleting too many snapshots at once with any tool. Delete few > and let filesystem stabilize before proceeding. OK, thanks for the tip. > For deduplication tool to be useful you ought to have some duplicate data on > your live volume. Do you have any (e.g. many LXC containers with the same > distribution)? No, no containers and no duplication to that large extent. > P.S. I still think you need some off-system backup solution too, either > rsync+snapshot-based over ssh or e.g. Burp (shameless advertising: > http://burp.grke.org/ ). I agree, but that's beyond the scope of the current problem I'm trying to solve. However, I'll check out Burp once I have a base configuration that is working satisfactorily. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
