> Now I guess it would be a good idea to get writes done properly, > even if it means make them slow (like with SVM). The end result > would be - do you want fast wrties/slow reads go ahead with > raid-z; if you need fast reads/slow writes go with raid-5. > > btw: I'm just thinking loudly - for raid-5 writes, couldn't you > somewhow utilize ZIL to make writes safe? I'm asking because we've > got an ability to put zil somewhere else like NVRAM card...
But the safety of raidz (and the overall on-disk consistency of the pool) does not currently depend on the ZIL. It instead depends on the fact that blocks are never modified in-place, but written first, then activated atomically. So I guess this depends on how the R5 is implemented in ZFS. As long as all writes cause a new block to be written (which has a full R5 stripe?), then the activation will be atomic and there is no write hole. The only problem comes if existing blocks were modified (and that would cause problems with snapshots anyway, right?) -- Darren Dunham [EMAIL PROTECTED] Senior Technical Consultant TAOS http://www.taos.com/ Got some Dr Pepper? San Francisco, CA bay area < This line left intentionally blank to confuse you. > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
