Hi! thanks for reply. > The BBWC is much more useful than the write cache on > the X25-E since > the X25-E's write cache is volatile and therefore may > cause harm to > your data. According to reports I have seen, the > X25-E write IOPS > reduces by a factor of five when its write cache is > disabled.
Use the BBWC to maintain high IOPS when X25-E's write cache is disabled? > I find this difficult to believe. I doubt that it > disables the > wear-leveling algorithm since then the product might > only survive for > hours or days before burn-out. There may be more > low-level writes > though which could result in quicker wear. At some report I have seen, write cache is necessary for wear-leveling. Should I switch off the X25-E's write cache? > Use ZFS for the RAID if you can. Use the BBWC to > reduce the latency > for small write I/Os. The serser has RAID card, so I can use hardware(Adaptec's) RAID(the file system is ZFS). Should I use ZFS for the RAID? > Since you mention mail server, it is useful to know > if the type of > mail server you are setting up involves a lot of > synchronous writes. > The best thing you can do is to install a lot of RAM > in your server to > minimize the amount of reads and writes. Lots of RAM > will reduce the > amount of write activity since writes can be > postponed for up to 30 > seconds, and mail folders may be updated many times > in the mean time. > With enough RAM installed, you will see almost all > writes, with > practically no reads. I think the IOPS is important for mail server, so ZIL is useful. The server has 48GB RAM and two(ZFS or hardware mirror) X25-E(32GB) for ZIL(slog). I understand the ZIL needs half of RAM. I am sorry for a lot of question. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
