Re: [zfs-discuss] ZFS unit of compression

2010-02-27 Thread Thanos Makatos
I have implemented a virtual block device in Linux that transparently compresses and decompresses data. In my implementation, the unit of compression is 4K. Multiple variable-size compressed blocks are stored in the same physical block, which in principle requires a read-modify-write sequence.

Re: [zfs-discuss] ZFS unit of compression

2010-02-27 Thread Richard Elling
On Feb 27, 2010, at 11:00 AM, Thanos Makatos wrote: I have implemented a virtual block device in Linux that transparently compresses and decompresses data. In my implementation, the unit of compression is 4K. Multiple variable-size compressed blocks are stored in the same physical block,

[zfs-discuss] ZFS unit of compression

2010-02-19 Thread Thanos Makatos
Hello. I want to know what is the unit of compression in ZFS. Is it 4 KB or larger? Is it tunnable? Thanks. Thanos -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org

Re: [zfs-discuss] ZFS unit of compression

2010-02-19 Thread Darren J Moffat
On 19/02/2010 15:43, Thanos Makatos wrote: Hello. I want to know what is the unit of compression in ZFS. Is it 4 KB or larger? Is it tunnable? I don't understand what you mean. For user data ZFS compresses ZFS blocks these would be 512 bytes minimum upto 128k maximum and depend on the