Am Mittwoch, 23. Dezember 2015, 11:45:28 CET schrieb Neuer User: > Hello Hi. > I want to setup a small homeserver, based on a HP Microserver Gen8 (4GB > RAM, 2x3TB HDD + 1x120GB SSD) and Proxmox as distro. > > The server will be used to host a (small) number of virtual machines, > most of them being LXC containers, few being KVM machines. One of the > LXC containers will host a fileserver with app 1 TB of data and another > one a backup system for the desktops / laptops in my household, thus > probably holding quite a lot of files. The lxc containers will use the > filesystem of the proxmox host, the KVM machines probably raw disk files > (or qcow2). > > I would like to combine high data integrity with some speed, so I > thought of the following layout: > > - both hdd and ssd in one LVM VG > - one LV on each hdd, containing a btrfs filesystem > - both btrfs LV configured as RAID1 > - the single SDD used as a LVM cache device for both HDD LVs to speed up > random access, where possible > > Now, I wonder if that is a good architecture to go for. Any input on > that? Is btrfs the right way to go for, or should I better go for ZFS > (and purchase some more gigs of RAM)? > > Will there be any problems arising from the lvmcache? btrfs only sees > the HDDs, LVM does the SDD handling. As far as I understand this way you basically loose the RAID 1 semantics of BTRFS. While the data is redundant on the HDDs, it is not redundant on the SSD. It may work for a pure read cache, but for write-through you definately loose any data integrity protection a RAID 1 gives you. Of course, you can use two SSDs and have them work as RAID 1 as well. There is a patch set for in-BTRFS SSD-caching. It consists of a patch set to add hot data tracking to VFS and a patch set for adding support in BTRFS. But I didn´t see anything of these in quite some time. Happy christmas, -- Martin -- 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
