3PAR Users Group

A Storage Administrator Community




Post new topic Reply to topic  [ 10 posts ] 
Author Message
 Post subject: Editing CPG RAID characteristics
PostPosted: Wed May 16, 2018 12:27 pm 

Joined: Wed May 16, 2018 12:24 pm
Posts: 7
Am I right in thinking that, when the RAID characteristics for a CPG are altered, all new LD creation will use the new RAID characteristics and that, when tunesys is performed, all existing LDs will be recreated using the new RAID characteristics? Thanks in advance.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Wed May 16, 2018 12:58 pm 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 702
Location: Europe
Yes.

Just watch out for failed tuneld tasks when running tunesys.

Showld (-d) will show the characteristics for each LD so you can verify when its done.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Wed May 16, 2018 10:41 pm 
Site Admin
User avatar

Joined: Tue Aug 18, 2009 10:35 pm
Posts: 1175
Location: Dallas, Texas
Precisely.

_________________
Richard Siemers
The views and opinions expressed are my own and do not necessarily reflect those of my employer.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Fri May 18, 2018 8:19 am 

Joined: Wed May 16, 2018 12:24 pm
Posts: 7
Thanks for the assistance, folks. Much appreciated.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Mon May 21, 2018 1:51 am 

Joined: Sat Jan 07, 2017 3:50 am
Posts: 22
Hi, any more clarification around failed tuneld tasks.
We had a lot after adding extra capacity to our 3PAR and running tunesys.
In our case tunesys was only started to balace data over the system, not to tune some params like raid5 to raid6. Maybe nothong to do with it, but instead of having beter backend response we saw some customer set alerts about response time (+ 9ms for SSD)


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Mon May 21, 2018 2:15 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 702
Location: Europe
You saw increased latency after running tunesys or during tunesys? And also what is the rule?

If after, I would check the load if that has changed.
If during, which 3PAR OS version are you running? And what types of volumes you got? Tunesys will add some load to the system as it is redistributing the data across the nodes, ports, cages and disks. I'm not sure to what granularity it works, but I would assume some latency spikes if you are trying to access blocks which are being tuned at the same time. I don't recall which patches but I seem to remember some tunesys and latency related fixes in some 3.2.2 patches for MU2, 3 and 4 maybe 1 1/2 to 2 years back. So if you're lagging behind on patches it might make it worse.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Mon May 21, 2018 12:55 pm 

Joined: Sat Jan 07, 2017 3:50 am
Posts: 22
We saw increased latency for the first time after adding additional SSD (#32) to the existing #64 and after tunesys was run (with tuneld errors seen). Running 3.3.1 EMU1 with the latest patches. First we saw > 3ms response on the backend . Nothing to worry about (HPE answer). Then we saw >5ms response on the backend and later on for more than one 5 minutes intervals a > 10 ms response on the SSD backend. Of course these are spikes seen , not all day and not every day.
We were suspicies about the tuneld errors seen with not good HPE explanation. One should not expect poor backend performance when adding extra hardware (SSD's). At this moment a HPE specialist is looking at the performance metrics to have an explanation.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Tue May 22, 2018 11:54 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 702
Location: Europe
Without a lot of info here, I'm thinking that this sounds like some node issues. Would be nice to hear what they find out.

Just out of curiousity.. SSDs and 3.3.1... Are you running dedupe and if so, what version?


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Tue May 22, 2018 4:18 pm 

Joined: Sat Jan 07, 2017 3:50 am
Posts: 22
we did implement dedupe (old version) for all vmware data (linux and windows) in production. The profit was 1,1/1 so we did un-dedupe again (best practices). Maybe in the future we will dedupe the VDI environment with the new dedupe version.
We also compressed everything in development and acceptance environment but went back also after some issues. Waiting now for 3.3.1 MU2 and written in blood that this is the OS without compaction issues.


Top
 Profile  
Reply with quote  
 Post subject: Re: Editing CPG RAID characteristics
PostPosted: Wed May 23, 2018 2:05 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 702
Location: Europe
Just checking, you are aware of the checkvv command with the -dedup_dryrun , -compr_dryrun (3.3.1 and later) and dedup_compr_dryrun(3.3.1 and later) commands to check for possible savings prior to converting? :)


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 


Who is online

Users browsing this forum: No registered users and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group | DVGFX2 by: Matt