MSA Storage

CPG nearly full - Help

 
robertoaxity
Occasional Advisor

CPG nearly full - Help

Hello guys,

I new in storage system, i have a 3par HPE 7200c, i have:

Summary Storage System

Allocated: 17 TB - Free: 8 TB

CPG

Fc_r5 - Raid 5 - Allocated: 13.5 TB (95%) - Free: 614 GB - Used: 12.9TB

So if have 8TB free, how i can increase the size of the cpg, because this are in 95%?

I use hpe 3par management console.

Thanks very much for your help.

Regards

3 REPLIES 3

Re: CPG nearly full - Help

If you really want to learn 3PAR then start using command line.

As per the details you have share it's not clear how much is your total raw space in your system. As you have mentioned only one CPG which is FC so I am assuming all are FC drives present in the system.

I am assuming 17TB raw space used and 8TB raw free space available in system. In order to get clear idea use below command,

showpd -c

Now to explain "Fc_r5 - Raid 5 - Allocated: 13.5 TB (95%) - Free: 614 GB - Used: 12.9TB" --> LD allocated space is 13.5TB, out of which 12.9TB used for data and 614GB free out of 13.5TB LD allocated space. This means if any new write IO comes  for any VV which is part of FC_r5 then it will use 614GB first.

Please note FC_r5 will show you logical space which means with RAID overhead. If you want to understand how much LD allocatable space left in FC_r5 then use this command,

showspace -cpg FC_r5

Out of this output look for "LDFree" column and this is actually LD allocatable space free which can be use in future. So your objective is to increase this LDFree column space. You can achive this by compacting FC_r5 CPG. In order to check if any space can be reclaim use below command,

compactcpg -dr FC_r5

If this indicates space reclaim possible then go for below command,

compactcpg -f FC_r5

Please note if too much space need to reclaim with the help of compactcpg then better to do it in out of office hours or in weekend.

If you want to understand space for the entire system then use below command,

showsys -space

Basically we increase or decrease space at the raw space level. CPG is just a template which actually shows how much space available as per the parameter defined in CPG. If you have multiple CPGs with same tier for example in this case FC tier. Let's say for example your total FC raw space 30TB, then FC_r1 which actually created with RAID1 and it will show LDFree as 15TB. Same 30TB FC raw space if you see for FC_r5 you can see around 22TB because this was created with RAID5. So 30TB raw space you are seeing as 15TB and 22TB at the same time. So if any VV part of these VVs start using space then it will decrease from both because both actually same space.

 

Hope this helps!
Regards
Subhajit

I am an HPE employee

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robertoaxity
Occasional Advisor

Re: CPG nearly full - Help

Hello SUBHAJIT, and thanks for your helps.

3ParImcruz01 cli% showpd -c

48 total 26208 16573 0 8543 0 0 0 0 0 1092 0 0

 

3ParImcruz01 cli% showspace -cpg FC_r5
--------------------------(MB)---------------------------
CPG ----EstFree---- -------Usr------- ----Snp---- ----Adm---- -Capacity Efficiency-
Name RawFree LDFree Total Used Total Used Total Used Compaction Dedup
FC_r5 8742912 7285760 13522176 13522176 347904 0 24576 17792 2.1 -

In this point, i have a 7TB according "LDFree" what can i use with the compactcpg, right?

What happens if the cpg arrive to 100%

-the data blocks and the host cant read or write? or the host only cant  write?

3ParImcruz01 cli% showsys -space
------------- System Capacity (MB) -------------
Total Capacity : 26836992
Allocated : 18088960
Volumes : 16717824
Non-CPGs : 0
User : 0
Snapshot : 0
Admin : 0
CPGs (TPVVs & TDVVs & CPVVs) : 16717824
User : 16226607
Used : 16226607
Used (Bulk VVs) : 0
Unused : 0
Snapshot : 417489
Used : 0
Used (Bulk VVs) : 0
Unused : 417489
Admin : 73728
Used : 53376
Used (Bulk VVs) : 0
Unused : 20352
Unmapped : 0
System : 1371136
Internal : 252928
Spare : 1118208
Used : 0
Unused : 1118208
Free : 8748032
Initialized : 8748032
Uninitialized : 0
Unavailable : 0
Failed : 0
------------- Capacity Efficiency --------------
Compaction : 2.1
Dedup : --------

Thanks very much

 

 

 

Re: CPG nearly full - Help

Please note showpd -c output shows size in GB and showsys -space shows space in MB but both command output shows raw space means without RAID overhead. (for simple I have shown GB and MB, not considering GiB or MiB)

As per showpd output total raw space = 26208GB
As per showsys output total raw space = 26836992MB = (26836992/1024)GB = 26208GB

As per showpd output Used chunklets = 16573 = 16573GB and Spare chunklets = 1092 = 1092GB which means total allocated space = 16573GB + 1092GB = 17665GB
As per showsys output Allocated space = 18088960MB = (18088960/1024)=17665GB

As per showpd output Free space = 8543GB
As per showsys output Free space = 8748032MB = (8748032/1024)GB = 8543GB

Rest all components from showsys output you can understand easily where actually your system space getting utilized

Now coming to FC_r5 which is actually CPG and it should show space with RAID overhead.

Here LDFree shows approx 7TB which means when any new write comes system will create LDs by taking space out of it.

Look at Usr-> Total and Usr->Used. Both shows 13522176MB which means till now whatever LD space got allocated that much only got used to store data. It means no space wastage.

Now coming to Snp-> Total, it shows 347904MB and Snp->Used shows 0MB. This means there is no snapshot space getting used. We can reclaim back space out of it by the help of compactcpg. This is the main job of compactcpg. It check Snp-> Total and Snp-> Used. If difference too much then compactcpg can reclaim space which will get add with LDFree. It means your LD allocatable space will increase. In turn your system raw free space which is 8543GB will increase. Please note compactcpg is not automatic. You need manually run as I shown in my last post.

Now if anypoint you see LDFree column shows 0 then there is no space left in the system for this CPG to create LD based on the CPG parameter defined. If you have actually raw space available in the system then LD creation will happen but same CPG will give you alert like CPG grown with degraded parameters. That time you need to modify CPG or add more drives or need to take necessary actions to fix this situation.

If any point your showpd free space shows 0 then you can't write anymore. So as admin you need to look for this area primarily.

 

Hope this helps!
Regards
Subhajit

I am an HPE employee

If you feel this was helpful please click the KUDOS! thumb below!

*************************************************************************


I work for HPE
Accept or Kudo