Which configuration is recommended for New VNXe with 6*600 GB SAS

Hi Manu Thanks for your post,

VNXe OE will store in internal flash ?? but as per capacity calculator report OE is consuming the 0.19% (194 GB)  of space.

In this case if i go with Raid 10 with out hot spare, here three mirror sets in a striped set work together to provide fault tolerance  in three disks , so Raid 10 will give better performance than raid 5. correct me if I m wrong.

which is best option Raid 10 or Raid 5 ??

Thank you,

Gurivi Reddy

Leo Thanks for your reply,

VNXe Vault drives is consuming 48 GB on each drive with Raid 1 or Raid 3, here my query is OE is stored on vault drives with Raid 1 / 3,  now If i configure Raid 5(4+1) on first five disks, how it will work on back ground ??

Hello Gurivi,

When we create a storage pool, user LUNs are created internally using the selected RAID type. We can stripe different types of RAID groups on the same disks. So we have OE LUNs (of type RAID 1 and 3) and user LUNs (of user selected RAID type) on the vault drives. Perhaps the image below would explain how this works:

In the image above, LUN 1,3,4 are created for user data (when you create a performance pool using disk 0,1,2,3,4). The 8xxx LUNs are the default system LUNs that keep OE data. This is very OS internal info, and its access/view is hidden to the user.

Hope this helps!

Hi Shardul,

Agreed, but still wondering about different types of raid groups on same disks, can you share if you have any documents to get in deep understanding and architecture of vault drives.

Thank you

Gurivi,

On the previous image, the FRUs are the physical disks. When striping LUNs across those disks, we do not use the entire disk capacity.

The 8xxx LUNs are system defined LUNs (with system defined RAID types), and as is clear, uses disks 0,1,2,3. However, the remaining space on these disks can be used for creating user RAID type LUNs (In the above example RAID 5).

I'm afraid there is no documentation available for VNXe's vault drive architecture. The OE data is kept hidden and the available space on the first drives can be used for creating Storage pools.

Thanks

Hi GuriviReddy,

Please do not refer to VNX documents for VNXe questions. VNX and VNXe have different architecture and are different in configuration aspects.

When it comes to configuring User pools you don't have much of choice of your own like you do in VNX. Depending on what type of disks you have (SAS, NLSAS or Flash) you need to select RAID type. RAID type used by vault drives is completely internal and does not affect what type of RAID you chose for User space. The concept of VNXe is to make it simple and easy to configure.

In your answer above (a) is not possible in VNXe,

(b) In case of SAS you create RAID5 (4+1), so on one disk 48GB is not used. In case of NLSAS RAID6 (4+2) similar thing happen on two disks.

As per EMC tech vault drives document, The usable capacity in first 4 (0-3) drives = 600 GB – 48 GB => 552 GB. Drives 4, 5 useable capacity is full 600 GB, green box shows useable capacity:

This space can be used two ways:

(a) You can use the available space on the first 4 drives for a stand-alone RG or NAS/Block Pool. For example: RAID 5 (3+1) will give you almost 1.6 TB usable AND use the remaining drives as another RG or part of a pool. There is no space wastage in this case.

(b) You can create a RG that spans across all the 6 drives as shown by the black square going across all 6 drives. This gives widest stripe configuration for RAID Group *but* you only get 552 GB of space from all 6 drives and 48 GB on the drive 4 and 5 is wasted.  ( don’t recommend this).

(c) For larger systems assign the extra 2 or 4 drives as hot spares, or as ‘buffer space’ for when the customer needs to add storage in case they wait until they are 98% full to order it.

Hi GuriviReddy,

Please also refer to the following contents

Depending on the intended application usage, the VNXe disk configuration provides different storage pool configuration options.

1. 1. 1. • General purpose storage
           Shared folder, Generic iSCSI, VMware, and Hyper-V

           The following table lists the options in the Disk Configuration wizard that apply to shared folders, generic iSCSI storage resources, and VMware or Hyper-V datastores intended for general purpose usage:

           Star Rating	Disk	RAID	Perf	Capacity	Cost
           Three star (best)	SAS	RAID 5 (6+1) or RAID 5 (4+1)	Medium	High	Medium
           Two	NL-SAS	RAID 6 (4+2)	Low	High	Low
           One	SAS	RAID 10 (3+3)	High	Med/Low	Med/High
           None	Flash	RAID 5 (4+1)	High	Medium	High

         • Exchange storage

           The following table lists the options in the Disk Configuration wizard that apply to storage intended for Exchange Server usage:

           Recommendation	Disk	RAID	Perf	Capacity	Cost
           Three star (best)	Flash	RAID 5 (4+1)	High	Medium	High
           Two star	SAS	RAID 10 (3+3)	High	Med/Low	Med/High
           One star	SAS	RAID 5 (6+1) or RAID 5 (4+1)	Medium	High	Medium
           None	NL-SAS	RAID 6 (4+2)	Low	High	Low

         • Backup storage
           Shared folder and Generic iSCSI

           The following table lists the options in the Disk Configuration wizard that apply to shared folders and generic iSCSI storage resources intended for backup storage:

           Recommendation	Disk	RAID	Perf	Capacity	Cost
           Three star (best)	NL-SAS	RAID 6 (4+2)	Low	High	Low
           Two star	SAS	RAID 5 (6+1)	Medium	High	High
           One star	SAS	RAID 10 (3+3)	High	Med/Low	Med/High
           None	Flash	RAID 5 (4+1)	High	Medium	High

         • Database storage
           Shared folder, Generic iSCSI, VMware, and Hyper-V

           The following table lists the options in the Disk Configuration wizard that apply to Shared Folders, generic iSCSI storage resources, and VMware or Hyper-V datastores intended for database storage:

           Recommendation	Disk	RAID	Perf	Capacity	Cost
           Three star (best)	Flash	RAID 5(4+1)	High	Medium	High
           Two star	SAS	RAID 10(3+3)	High	Med/Low	Med/High
           One star	SAS	RAID 5 (6+1) or RAID 5 (4+1)	Medium	High	Medium
           None	NL-SAS	RAID 6 (4+2)	Low	High	Low

         • VM datastores
           VMware and Hyper-V

           The following table lists the options in the Disk Configuration wizard that apply to VMware and Hyper-V datastores intended for general purpose usage:

           Recommendation	Disk	RAID	Perf	Capacity	Cost
           Three star (best)	SAS	RAID 5 (6+1) or RAID 5 (4+1)	Medium	High	Medium
           Two star	SAS	RAID 10 (3+3)	High	Med/Low	Med/High
           One star	Flash	RAID 5 (4+1)	High	Medium	High
           None	NL-SAS	RAID 6 (4+2)	Low	High	Low

Hi Dinesh,

Yes, I agree with you like VNX in VNXe we don't have much choice, either we need to create performance / capacity / availability pools,

if I create a pool with 20 disk's with Raid-5(4+1), it will create internally four private raid groups in that pool,  on only first private Raid group in that pool on one disk 48 GB is not used or on entire 20 disks 48 GB in that pool is not used ??

Hello Gurivi,

Even if you create a big pool with all drives, you will not lose out 48GB on all drives. In the case you presented, space will only be lost on the first 5 disks (the first internal Raid Group).

It is however, a good idea to keep the vault drives in a separate 'Storage Pool'. Since these disks are used to serve some operating system information, it would be a good idea to keep performance sensitive resources off of it.

Thanks