On Wed, 7 Apr 2010, Jason S wrote:
I was actually already planning to get another 4 gigs of ram for the box right away anyway, but thank you for mentioning it! As there appears to be a couple ways to "skin the cat" here i think i am going to try both a 14 spindle RaidZ2 and 2 X 7 RaidZ2 configuration and see what the performance is like. I have a fews days of grace before i need to have this server ready for duty.
It will be very difficult to test actual performance because the pool will behave differently after it has been in service for six months or a year. There will be some fragmentation and if the pool is allowed to grow to close to 100% full, the fragmentation in that last data may be severe. If you have background zfs snapshots enabled, then the performance is likely to degrade more quickly than if you don't use snapshots since the disks will tend to be more full, and the disk heads will need to seek further.
If you choose the 14 spindle raidz2, the chances are good that you will soon be complaining about performance. You mentioned that there may be four simultaneous readers and it is worth noting that this is already twice the number of vdevs if you go for the two vdev solution. With two vdevs and four readers, there will have to be disk seeking for data even if the data is perfectly sequentially organized.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
