saran456
1 Copper

Dell Compellent LUN Size for Hyper -v 2012 host

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We are going to provision a storage from Dell compellent SC 4020 for 48TB to a new environment, we end up in a confusion to decide with the size of LUN. Please suggest.

 

Option1 : 24 * 2 TB =48 TB

 

Option 2: 8 * 6 TB =48TB

Model : SC 4020

Host details : Microsoft Hyper –v 2012 ( it can support up to 64 TB LUNs)

 Thanks
Saran

 

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DELL-Donald Wi
5 Rhenium

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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Hello, 

 The array isn't impacted by volume size.  It's all just blocks of data.  At the SCSI level, a LUN has a negotiated queue value.  From 0 - 255.  Typical values are 64-128.  When that limit is hit, I/O to that LUN is paused until IO is processed by the storage, and the queue drained.   So if you had one 64TB LUN that would mean one queue per LUN.  That can be an limit on performance. Additionally,  how OS's cache LUNs comes into play as well.  More volumes can produce higher cache hit rates.  

 Again a lot goes to what the application is.  For example with SQL, I always give them their own volumes. I never run multiple instances of SQL on the same volume. 

 Another benefit is it's easier to monitor performance if you have more volumes.  

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

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DELL-Donald Wi
5 Rhenium

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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Hello, 

 There are no standard volume size recommendations..  It should be based on your needs. I will say that especially with Virtual environments that more/smaller volumes tend to do better than one or two MEGA volumes.   

 How large are the VMs going to be?  

 You also don't want to use all the storage the array provides.  It needs unallocated space in order to operate correctly. 

 Regards,

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

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saran456
1 Copper

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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we have a 100TB of total storage & we are going use 48TB . Out of 48TB , 45TB will be used for File server in a VM.

Even my consideration is to go with a smaller LUN size , however i don't find a strong reason /document to support that ( as dell compellent blocks will be partition to be 2MB page size ultimately)

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DELL-Donald Wi
5 Rhenium

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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Hello, 

 The array isn't impacted by volume size.  It's all just blocks of data.  At the SCSI level, a LUN has a negotiated queue value.  From 0 - 255.  Typical values are 64-128.  When that limit is hit, I/O to that LUN is paused until IO is processed by the storage, and the queue drained.   So if you had one 64TB LUN that would mean one queue per LUN.  That can be an limit on performance. Additionally,  how OS's cache LUNs comes into play as well.  More volumes can produce higher cache hit rates.  

 Again a lot goes to what the application is.  For example with SQL, I always give them their own volumes. I never run multiple instances of SQL on the same volume. 

 Another benefit is it's easier to monitor performance if you have more volumes.  

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

View solution in original post

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saran456
1 Copper

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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Its not related to this topic. Do we have any procedure to change the management ip in compellent

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DELL-Donald Wi
5 Rhenium

RE: Dell Compellent LUN Size for Hyper -v 2012 host

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Hello, 

 I believe so yes.  I"m not an expert with the CML product line. 

 I would suggest opening a support case.  They can assist you with making changes. 

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro