On 12/03/2021 18:25, Philip Brown wrote:
well that is a very interesting statistic. Where do you come up with the 30GB partition size limit number? I believe it is using 28GB SSD per HDD disk :-/ So you are implying that if I "throw away" 1/8 of my HDDs, so that I can get that magic number 30GB+ per HDD, things will magically be improved? Before I do that kind of rework, I would like to better understand the theory behind that please :) I vaguely recall reading something about WAL, ssd, and " db mostly". I believe there is some way to check the status of that, but google search is being difficult without a more specific search term. ----- Original Message ----- From: "Maged Mokhtar" <mmokhtar@xxxxxxxxxxx> To: "Philip Brown" <pbrown@xxxxxxxxxx> Cc: "ceph-users" <ceph-users@xxxxxxx> Sent: Friday, March 12, 2021 8:04:06 AM Subject: Re: Question about delayed write IOs, octopus, mixed storage as a side issue, i do not know how cephadm would configure the 2 x 100 GB SSDs for wal/db serving the 8 HDDs, you need over 30 GB partition size else it would result in db mostly on slow HDDs. /maged
I do not believe you are currently being slowed by this yet, else your cluster will show a "WARN: BlueFS spillover detected"
but it will eventually happen as you write more and your db expands. You can read more in this post by Nick Fisk http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-October/030913.html /maged _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
