Linked by moondevil on Wed 11th Jan 2012 00:10 UTC
Windows The latest blog entry from Steven Sinofsky about Windows 8 describes the Storage Spaces functionality . From the blog entry it seems Windows 8 is getting something ZFS-like. The Storage Spaces can be created in the command line via Powershell, or in the Control Panel for the ones that prefer a more mouse-friendly interface.
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RE[4]: OSNews RTFA and comments
by hechacker1 on Sat 14th Jan 2012 02:22 UTC in reply to "RE[3]: OSNews RTFA and comments"
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Without over-provisioning at the beginning, you are forced to run utilities (even in Linux) to:

1. Expand the volume onto a new disk.

2. Allow the underlying storage pool to recalculate and distribute parity for the new disk (which affects the entire pool).

3. Resize the file system on top with a tool. This can be fast, but it can also be slow and risky depending on the utility. NTFS generally can resize up well. Still, it's an operation were you probably want a backup before doing.

In contrast with over provisioning, you don't have to do the above steps. It's handled automatically and from the start.

With regards to having a SSD as a backing device, it allows you to speed up parity in situations like RAID 5. The read-modify-write cycle is slow to perform for a HDD, but fast for a SSD. Especially in cases where small writes dominate the workload. A SSD allows for fast random r/w, but then writes to the HDD pool can happen in a serialized operation.

Some RAIDs get around this problem with a volatile cache, but you are risking data to minimize the parity performance hit. Using an SSD means it's non-volatile and the journal could playback to finish the operation. I guess you could do it on a regular HDD, but you would still be measuring performance latency in 10s of milliseconds instead of <1ms. It's an order of magnitude difference.

It's all theoretical at this point, but Microsoft briefly mentioned having an SSD would be faster. We'll have to wait for more details.

Edited 2012-01-14 02:26 UTC

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