L2 cache not working

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bigflyer
Posts: 7
Joined: Wed Apr 29, 2015 10:03 am

Wed Apr 29, 2015 10:05 pm

I've added an L2 cache to a device using the method described here: https://forums.starwindsoftware.com/vie ... f=5&t=4104. I restarted Virtual SAN, but the L2 cache is not appearing on the right. Using Windows Resource monitor it doesn't look as if any activity is happening to the cache file either. Also, the 'last modified' date/time on disk isn't updating - so it looks like it's just not being recognised.

I've also tried setting up a new device with L2 cache defined during creation, and it looks like that's not working either.

Is this a problem with this version of the software (8.0.7929) or am I doing something wrong? Is there any way I can check that Virtual SAN is recognising that there should be an L2 cache defined?
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sloopy
Posts: 12
Joined: Wed Jun 08, 2011 7:49 pm

Thu Apr 30, 2015 2:42 am

I came here looking for similar answers. Are you creating a thick provisioned disk? The only way I see that it works is using thin/lsfs. I'm hoping this is just a bug that can be squashed and released quickly.
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sloopy
Posts: 12
Joined: Wed Jun 08, 2011 7:49 pm

Thu Apr 30, 2015 2:56 am

Just saw this quote from yesterday. Apparently there are issues with L2 cache but it does not say what exactly.

https://forums.starwindsoftware.com/vie ... =15#p23737
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bigflyer
Posts: 7
Joined: Wed Apr 29, 2015 10:03 am

Thu Apr 30, 2015 2:29 pm

The thread I referenced (dated 20th April) says:

"We have some issues related to L2 cache in Write-Back mode, thus, meanwhile we recommend using L2 cache in Wright-Through mode only. "

As I'm doing it in write-through mode, I thought it would be OK.
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Oles (staff)
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Posts: 91
Joined: Fri Mar 20, 2015 10:58 am

Fri May 01, 2015 2:55 pm

Hello guys!

Unfortunately L2 cache is temporary disabled.
We are improving it,and it will be enabled again in our next build. ETA is 2 weeks.

Thank you for you understanding and patience.
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santiagocastro
Posts: 6
Joined: Thu May 07, 2015 8:52 am

Thu May 07, 2015 9:00 am

Same here, when using LSFS volume, L2 cache appears disabled and when creating thick volume, it does not appear anyway.

When upgrading from build 6884, contents of a volume previously created using L2 cache have dissapeared!!!!!
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sloopy
Posts: 12
Joined: Wed Jun 08, 2011 7:49 pm

Mon May 11, 2015 3:41 pm

Oles-- is there a firm date yet on the new release which you say will allow L2 cache on a thick image? Will this also add back deduplication support on thick images?
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Oles (staff)
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Wed May 13, 2015 4:45 pm

Hello!

Approximate time for this release to come out is 4 weeks. Dedup on thick images was always disabled, so i am not sure i understand your question.
Although, you could enable Windows deduplication for thick images.
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sloopy
Posts: 12
Joined: Wed Jun 08, 2011 7:49 pm

Wed May 13, 2015 6:43 pm

Back in v6 we were able to do deduplication. Perhaps it was thin provisioned, but I guess my question would be will there ever be an option to do deduplication on a non-LSFS LUN? I don't think LSFS is there quite yet after the horror stories on the forums of data loss and the virtual image sizes growing uncontrollably. We experienced this ourselves where we had about 20GB free on the Windows partition. A VM left untouched overnight filled the 25GB and locked the LUN up. Right now the 2-3x extra space requirements does not make sense from the perspective of space/power/cooling/cost (i.e. if I have 2 JBOD's on each of 3 Starwind nodes, I now need 6 JBOD's to accommodate the LSFS requirements).
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Branin
Posts: 31
Joined: Mon May 04, 2015 5:22 pm

Wed May 13, 2015 6:59 pm

Oles(staff) wrote:Hello!

Approximate time for this release to come out is 4 weeks. Dedup on thick images was always disabled, so i am not sure i understand your question.
Although, you could enable Windows deduplication for thick images.
Is this 4 more weeks from today? Back on May 01, the ETA was 2 weeks, which is roughly the end of this week. Is the new ETA is 2 more weeks, or 4 more weeks from now? Just curious.

Thanks!

Branin
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sloopy
Posts: 12
Joined: Wed Jun 08, 2011 7:49 pm

Thu May 14, 2015 3:58 pm

Are there any benefits to adding an SSD L2 cache in front of an all-SSD virtual image?
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Oles (staff)
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Posts: 91
Joined: Fri Mar 20, 2015 10:58 am

Fri May 15, 2015 4:23 pm

Hello Guys!

So the ETA for release has moved and our developers need 4 more weeks until this new build will be released.

Speaking about dedup on thick images, now we are not planning to add dedup on them, but may be this will be considered in future.

About L2 cache on SSD storage, no, there are no benefits in adding L2 cache for SSD storage.

Thank you for your questions, and please let me know if you have any left :)
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schraepf
Posts: 2
Joined: Wed May 27, 2015 12:14 pm

Wed May 27, 2015 12:17 pm

Hi Oles,

Curious if the release timeline you described is still on track, I ran into this yesterday and am anxious to test performance w/ the L2 cache enabled. Thank you!!!!
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jhamm@logos-data.com
Posts: 78
Joined: Fri Mar 13, 2009 10:11 pm

Wed May 27, 2015 8:09 pm

Will the new version support an L2 cache on a thick (non LSFS) disk?
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anton (staff)
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Thu May 28, 2015 11:25 am

All of them actually do this...
jhamm@logos-data.com wrote:Will the new version support an L2 cache on a thick (non LSFS) disk?
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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