Il 2020-09-09 21:53 John Stoffel ha scritto:
Very true, numbers talk, annecdotes walk...
Sure - lets try to gather some numbers from the data you posted before...
sudo lvcache status data/home +-----------------------+------------------+ | Field | Value | +-----------------------+------------------+ | cached | True | | size | 806380109824 | | cache_lv | home_cache | | cache_lv_size | 85899345920 |
You cache device is squarely in the 10x ballpark (ie: it is ~9.39x smaller than your SSD). Having ~10.64% more space would be nice, but hardly game-changer.
| read_hits | 138697828 | | read_misses | 7874434 |
You have 94.6% hit rate from your hotspot cache - compare this to an ideally managed tiered storage, with its 100% (ideal, not reasonable in real world) hit rate. Does it really change anything?
| write_hits | 777455171 | | write_misses | 9841866 |
And you have an even better ~98.7% write hit ratio. As you have a mirrored cache device, you should be able to set LVM for using a writeback cache without risking your data in case of a single cache drive failure. I suspect this would do wonder with your hit ratio - but again, testing is the only method to be sure.
Thanks for sharing your data! Regards. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx GPG public key ID: FF5F32A8 _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
