Some of my terminology may not be 100% accurate, so apologies in advance to the pedants on this list. ;)
On Tue, Jun 15, 2010 at 12:13 PM, CarlPalmer <dwarvenlo...@yahoo.com> wrote: > I have been researching different types of raids, and I happened across > raidz, and I am blown away. I have been trying to find resources to answer > some of my questions, but many of them are either over my head in terms of > details, or foreign to me as I am a linux noob, and I have to admit I have > never even looked at Solaris. > > Are the Parity drives just that, a drive assigned to parity, or is the > parity shared over several drives? > Separate parity drives are RAID3 setups. raidz1 is similar to RAID5 in that it uses distributed parity (parity blocks are written out to all the disks as needed). raidz2 is similar to RAID6. raidz3 (triple-parity raid) is similar to ... RAID7? Don't think there's actually any formal RAID levels above RAID6, is there? > I understand that you can build a raidz2 that will have 2 parity disks. So > in theory I could lose 2 disks and still rebuild my array so long as they > are not both the parity disks correct? > There are no "parity disks" in raidz. With raidz2, you can lose any 2 drives in the vdev, without losing any data. Lose a third drive, though, and everything is gone. With raidz3, you can lose any 3 drives in the vdev without losing any data. Lose a fourth drive, though, and everything is gone. > I understand that you can have Spares assigned to the raid, so that if a > drive fails, it will immediately grab the spare and rebuild the damaged > drive. Is this correct? > Depending on the version of ZFS being used, and whether or not you set the property that controls this feature, yes. Hot-spares will start rebuilding a degraded vdev right away. > Now I can not find anything on how much space is taken up in the raidz1 or > raidz2. If all the drives are the same size, does a raidz2 take up the > space of 2 of the drives for parity, or is the space calculation different? > Correct. raidz1 loses 1 drive worth of space to parity. raidz2 loses 2 drives worth of space. raidz3 loses 3 drives worth of space. > I get that you can not expand a raidz as you would a normal raid, by simply > slapping on a drive. Instead it seems that the preferred method is to > create a new raidz. Now Lets say that I want to add another raidz1 to my > system, can I get the OS to present this as one big drive with the space > from both raid pools? > Yes. That is the whole point of pooled storage. :) As you add vdevs to the pool, the available space increases. There's no partitioning required, you just create ZFS filesystems and volumes as needed. > How do I share these types of raid pools across the network. Or more > specifically, how do I access them from Windows based systems? Is there any > special trick? > The same way you access any harddrive over the network: - NFS - SMB/CIFS - iSCSI - etc It just depends at what level you want to access the storage (files, shares, block devices, etc). -- Freddie Cash fjwc...@gmail.com
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