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[zfs-discuss] Re: Solid State Drives?

Subject: [zfs-discuss] Re: Solid State Drives?
From: "Anton B. Rang"
Date: Fri, 05 Jan 2007 08:18:50 PST
> If [SSD or Flash] devices become more prevalent, and/or cheaper I'm curious 
> what
> ways ZFS could be made to bast take advantage of them?

The intent log is a possibility, but this would work better with SSD than 
Flash; Flash writes can actually be slower than sequential writes to a real 
disk.

Metadata accesses tend to be more random than data accesses, so separating 
metadata from data can be useful with most file systems. Whether this is also 
true for ZFS is unclear, since even sequential data access in ZFS results in 
random reads.

> You still need to know that the data is on the real drives
> before you can wipe that transaction from the
> transaction log right?

Yes; but if you allow the transaction log to grow to large sizes, you could 
eliminate the need to flush data to the real drives so frequently.  Given that 
random access doesn't cost any more than sequential access on an SSD, so that a 
large log doesn't hurt performance much, I suspect it would be possible to 
reduce the frequency at which the real cache is flushed.

Anton
 
 
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