ZFS and containers vs VMs

[bruceg]

I have used ZFS on spinners for several years and we strictly run VMs. We are deploying some new servers using SSDs for the first time, using raidz. I was told by someone that containers are the better choice. He posited that a VM is essentially a BLOB that sits in the same spot and it constantly being written to and thereby shortening the lifespan of the SSD because of the inordinate number of writes in that spot. He suggests that a container allows ZFS to allocate/manage storage and avoids this situation. Can someone confirm if this is so? I'm not opposed to using containers but want to know if I should.

 

[Dunuin]

All SSDs got wear leveling and there is nothing like fixed positions inside the SSDs. It will shuffle all data across the disk so every NAND cell should have the same amount of wear. And even if there would be no wear leveling shuffeling the data around, like with HDDs, because of ZFS there is no fixed place for a filesystem or virtual block device, because ZFS is a copy-on-write filesystem. Because it is CoW nothing will be overwritten, but added at the end of the journal. So every edit of a file will cause a write somewhere else.

 

[bruceg]

All SSDs got wear leveling and there is nothing like fixed positions inside the SSDs. It will shuffle all data across the disk so every NAND cell should have the same amount of wear. And even if there would be no wear leveling shuffeling the data around, like with HDDs, because of ZFS there is no fixed place for a filesystem or virtual block device, because ZFS is a copy-on-write filesystem. Because it is CoW nothing will be overwritten, but added at the end of the journal. So every edit of a file will cause a write somewhere else.

Thank you for replying. I guess I'll stay with VMs