Any gain in SSD cache disk?

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Robert Rehnmark

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Oct 30, 2012, 1:08:08 PM10/30/12
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I have a 3 GB pool (2x3GB in mirror) where I store data like iTunes-/iPhoto Libraries, movies, etc.
I have upgraded my boot drive to a 512GB SSD and now I have a spare 160GB SSD, do you think I would see any performance gains by using it as a cache drive or should I find some better use for it?

Thanks.
Robert

Jason

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Oct 30, 2012, 2:33:42 PM10/30/12
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It depends on bus speed, connection option like sata, FireWire, etc. , give it a go.... Best way to known in your instance. 

Jason
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Robert Rehnmark

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Oct 31, 2012, 4:53:51 AM10/31/12
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Den tisdagen den 30:e oktober 2012 kl. 19:33:45 UTC+1 skrev jasonbelec:
It depends on bus speed, connection option like sata, FireWire, etc. , give it a go.... Best way to known in your instance. 

Jason
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Yes, I was thinking that I would try it out.
All the drives are connected with SATA II on a quite powerful computer (i7 @ 3.4GHz with 12GB of RAM @ 1600MHz).
The performance is ok for my use but it's a bit frustrating with the "bursts" in transfer rate I'm experiencing.

Is it possible to remove a cache disk without destroying or messing up the pool?

Daniel Bethe

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Oct 31, 2012, 6:35:20 AM10/31/12
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Sorry, but MacZFS doesn't support L2ARC devices.

From: Robert Rehnmark <xca...@gmail.com>
To: zfs-...@googlegroups.com
Sent: Wednesday, 31 October 2012, 3:53
Subject: Re: [zfs-macos] Any gain in SSD cache disk?

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Fastmail Jason

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Oct 31, 2012, 7:41:19 AM10/31/12
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Dan is correct I believe. I had been looking at that before and will again.

Your getting a lot of 'bursting'? How many drives? Size? how's your pool setup? Are you saturating the bus? Asking because I see this on older systems I hacked up for ESATA, not so much a newer ones like Thunderbolt spec.


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Jason Belec
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Robert Rehnmark

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Oct 31, 2012, 9:08:08 AM10/31/12
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Den onsdagen den 31:e oktober 2012 kl. 12:41:19 UTC+1 skrev jasonbelec:
Dan is correct I believe. I had been looking at that before and will again.

Your getting a lot of 'bursting'? How many drives? Size? how's your pool setup? Are you saturating the bus? Asking because I see this on older systems I hacked up for ESATA, not so much a newer ones like Thunderbolt spec.


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Jason Belec
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My "mac" is based on a GA-X58A-UD7 motherboard with an i7-930 running at 3.4GHz and 12GB RAM.
When I copy a 16GB file from the old SSD to the new SSD (OCZ Vertex4, fast read/write, SATA III) I get a constant performance of 250MB/s.
When copying from new fast SSD (Vertex4) to RAM-Disk I get almost 400MB/s
The pool where I would like to increase read performance is a mirror of two 3TB Barracuda drives on the SATA II bus. It is created with ashift=12.
Don't know if it's possible to increase read speed but it would be nice.

Oh, I didn't think about until now but I am actually trying out the ZevoCE release now so maybe I should take it to that forum.. 

Fastmail Jason

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Oct 31, 2012, 9:20:09 AM10/31/12
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Yeah, kinda wrong group. ;)



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Jason Belec
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