Hi Migual, first at all: man zfs!
On 11.12.2017 13:40, Miguel González wrote: > Is it advisable to use sparse on ZFS pools performance wise? And > compression? Which kind of compression? Sparse or not doesn't matter on SSDs. I would use compression because of less r/w to the disc and modern CPUs can handle lz4 quite well. Also keep in mind: A sparse volume only stays sparse if trim/discard is used! volblocksize is important: ZFS is using 8k as default. For ZFS filesystem a recordsize of 128K is used. Some older test: zpool/vm-zvols/bsize_1k written 10.3G zpool/vm-zvols/bsize_1k logicalused 1.82G zpool/vm-zvols/bsize_4k written 2.60G zpool/vm-zvols/bsize_4k logicalused 1.76G zpool/vm-zvols/bsize_8k written 2.60G zpool/vm-zvols/bsize_8k logicalused 1.78G zpool/vm-zvols/bsize_16k written 1.87G zpool/vm-zvols/bsize_16k logicalused 1.70G zpool/vm-zvols/bsize_32k written 1.87G zpool/vm-zvols/bsize_32k logicalused 1.71G zpool/vm-zvols/bsize_64k written 1.72G zpool/vm-zvols/bsize_64k logicalused 1.72G zpool/vm-zvols/bsize_128k written 1.75G zpool/vm-zvols/bsize_128k logicalused 1.75G > Can I change a zpool to sparse on the fly or do I need to turn off all > VMs before doing so? No, sparse or not is set at creation. > Why a virtual disk shows as 60G when originally It was 36 Gb in raw format? > > NAME USED AVAIL REFER MOUNTPOINT > rpool/data/vm-102-disk-1 60.0G 51.3G 20.9G - Because of blocksizes. Check zfs get all and read theory about ZFS. Here's an example for a non-sparse 50GB Volume for a VM: zpool/vm-zvols/foobar 51.6G 2.19T 34.6G - zpool/vm-zvols/foobar used 51.6G zpool/vm-zvols/foobar referenced 34.6G zpool/vm-zvols/foobar compressratio 1.02x zpool/vm-zvols/foobar volsize 50G zpool/vm-zvols/foobar volblocksize 8K zpool/vm-zvols/foobar compression lz4 zpool/vm-zvols/foobar refreservation 51.6G zpool/vm-zvols/foobar usedbydataset 34.6G zpool/vm-zvols/foobar usedbyrefreservation 17.0G zpool/vm-zvols/foobar refcompressratio 1.02x zpool/vm-zvols/foobar written 34.6G zpool/vm-zvols/foobar logicalused 24.2G zpool/vm-zvols/foobar logicalreferenced 24.2G Andreas _______________________________________________ pve-user mailing list [email protected] https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user
