Hi, Thomas Deutsch wrote: > Hi > > I'm thinking about to change from Linux/Softwareraid to > OpenSolaris/ZFS. During this, I've got some (probably stupid) > questions:
don't worry, there are no stupid questions :). > 1. Is ZFS able to encrypt all the data? If yes: How safe is this > encryption? I'm currently using dm-crypt on linux for doing this. Encryption for ZFS is a planned feature, but not available now. See: http://www.opensolaris.org/os/project/zfs-crypto/ Another project is an encrypted loopback device called xlofi which can be used on top of ZFS: http://www.opensolaris.org/os/community/security/projects/xlofi/ I understand that both approaches are independent of the encryption mechanism, so one would be free to choose a suitably safe cypher that is supported by the Solaris Cryptographic Framework. > 2. How big is the usable diskspace? I know that a rai5 is using the > space of one disk for parity informations. A raid5 with four disk of > 300GB has 900GB Space. How is it with ZFS? How much space do I have in > this case? ZFS' RAIDZ1 uses one parity disk per RAIDZ set, similarly to RAID-5. ZFS' RAIDZ2 uses two parity disks per RAIDZ set. So, the amount of usable space can be computed by number of disks per RAIDZ set minus 1 or 2 depending on the algorithm times the minimum capacity per disk. Same calculation as with traditional RAID. But there are advantages for RAIDZ over traditional RAID-5: - No RAID-5 write hole. - Better performance through serialization of write requests. - Better performance through eliminating the need for read-modify-write. - Better data integrity through end-to-end checksums. - Faster re-syncing of replaced disks since you only need to recreate used blocks. - Compression can be easily switched on for some extra space depending of the nature of the data. See also: http://blogs.sun.com/roller/page/bonwick?entry=raid_z Best regards, Constantin -- Constantin Gonzalez Sun Microsystems GmbH, Germany Platform Technology Group, Client Solutions http://www.sun.de/ Tel.: +49 89/4 60 08-25 91 http://blogs.sun.com/constantin/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
