Open TheLinuxGuy opened 1 month ago
Also an important question, it seems like btrfs
filesystem is not in the supported filesystems list: https://open-cas.com/guide_system_requirements.html
Btrfs seems to be working okay in my testbench with OpenCAS... is OpenCAS team testing btrfs or planning to support btrfs
or any other advanced file system like zfs
? Ext4 did give me better benchmarks but I rather use btrfs
at minimum... this is not an issue with bcache.
@TheLinuxGuy Technically Open CAS should be able to handle any filesystem, as it conforms to the standard Linux bdev interface. So btrfs
and zfs
almost certainly work just fine. What "supported" means in our case is that we actually do test it for the listed filesystems. Open CAS has a quite extensive set of functional tests which we execute for each release. I'm not sure how much bcache developers test it with various filesystems - I was not able to find this information - but extending our tests set is certainly possible. So far we did not consider adding tests for the other filesystems because no one asked for them.
We'll try to evaluate how much would that cost to include btrfs
and zfs
in our testing scope. For the context, currently the full execution of Open CAS functional tests takes about a week (day and night), so the cost is not negligible. We value stability of the project, and as much as we'd like to support every single configuration and scenario, we first need to make sure that whatever we decide to support, we are able to do it in excellent quality over long period of time.
currently the full execution of Open CAS functional tests takes about a week (day and night), so the cost is not negligible. We value stability of the project, and as much as we'd like to support every single configuration and scenario, we first need to make sure that whatever we decide to support, we are able to do it in excellent quality over long period of time.
Understood, thank you for the detailed explanation and for the consideration.
XFS and EXT4 are reliable and great - but snapshotting, checksumming, btrfs-send/zfs-send are modern filesystem features that I feel are in demand. IIRC Facebook uses btrfs on all their production fleet. https://facebookmicrosites.github.io/btrfs/docs/btrfs-facebook.html
Question
Looking to ensure that I am using the correct settings to achieve my goal of always write/read from NVME disks and promoting data from HDD as soon as files are accessed.
Motivation
I'm comparing bcache to OpenCAS to see if it can fit my needs. I have some notes in one of my repositories here.
Background:
My goal is as follows:
Your Environment
OpenCAS version (commit hash or tag):
22.12.0.0855.master
Operating System:
Debian bookworm 12 - Proxmox
Kernel version:
6.8.8-2-pve
Cache device type (NAND/Optane/other): NVME WD Red SN700 1000GB__1
Core device type (HDD/SSD/other): 20TB 7200RPM disks
Cache configuration:
wb
4 [KiB]
always
nop
never
Other (e.g. lsblk, casadm -P, casadm -L)
lsblk
casadm -P
casadm -L