Hi all, I’m working with a software (Openstack Swift) which does a lot of filesystem metadata operations: - recursive listing - xattr get/set - deleting files - creating empty files (It also does "data" operations, of course) These days, HDDs gets bigger but theirs performances does not increase as much. On a bigger disk, there is more data, so statistically more request for data, but the I/O budget stays pretty much the same. We are considering various solutions to this issue. One of the most interesting idea is to store filesystem metadata on a faster device (SSD/NVMe). ZFS implemented this feature about a year ago [1]. Intel has been working on a generic solution called OpenCAS [2]. XFS had for a long time the realtime option which seems to provide that feature, even if it was not designed for this particular use case. I read various things, and it seems that in 2017 this feature was not considered stable, not even tested [3]. Since 2017, when looking at the git log, I found many commits mentioning this feature, as much as from 2005 to 2017. So my question is: what is the current state of realtime? Did it change and is now stable/production ready. If not, is there any willing to go this way to match this kind of use case? Maybe you even have an other idea to ensure good read/write performance on filesystem metadata? Thx for your answer. [1] https://github.com/zfsonlinux/zfs/pull/5182 [2] https://open-cas.github.io/ [3] https://patchwork.kernel.org/patch/9933237/#20895229 -- Romain
