EMC VNX – Unisphere – Quick overview

I already wrote few words about Unisphere in post EMC VNX – How to use Unisphere. In this post I would like to show you a little bit more in practice how you can start working with EMC Unisphere.

How to launch?

As I mentioned in my previous post, easiest way to launch is to fire up and Internet Browser and type the IP address of Control Station. TIP: You have to have Java installed and available.

When you see login screen just login with your credentials. If you log in for the first one you can probably login with the standard credentials:

* login: sysadmin
* password: sysadmin

Worked? Great. After you log in you should see screen like the one below:

Unisphere Dashboard

Unisphere Dashboard

I have added few comments in red. First thing you have to notice is that you see a Dashboard. If you have more then one VNX in the domain you are actually not yet login to the specific VNX, but for the overall dashbord (of course it depends on the Scope of your credentials, but I assume you login as a sysadmin).

If you would like to work / manage single storage system you have to choose it, either from drop-down list in top left corner, or click on the hostname below the menu.

Working with Storage Array

Once you have selected a desired VNX Array your Dashbord should change a little, and look more like:

Unisphere VNX Dashboard

Unisphere VNX Dashboard

It is opened in the same window. You have more specific information about your Array. First you see all important (recent) system alerts. On the right top window you should see basic information, hint: here you will find serial number, often needed 🙂

Let’s take a quick tour thru the menu options


Unisphere System menu

Unisphere System menu

Each menu have several options. You can either click on the top menu choise (System,Storage,Host,Data Protection etc.) or just hover over it and wait to more options to pop up. System have three choices:

  •  Hardware – here you can find all hardware information, from single harddrive information to FAN status.
  •  Monitoring and Alerts – all alerts are here, you can gather SP Event Logs, Notifications, Statistics and more, even schedule sending e-mail with statistics.
  •  Reports – place where you can generate reports


Unisphere Storage menu

Unisphere Storage menu

This tab will be probably often visited in your daily tasks. The number of options available here may vary depends on version, licenses etc. For example if you have VNX for file, you would see here much more :).

In this section you can actually provision Storage, create LUN’s or Storage Pools, etc. More detailed examples I will put in the short future.


Unisphere Host menu

Unisphere Host menu

In this tab the most important section is probably Storage Groups where you can define new, delete old or modify already existing Storage Groups. But of course to create a Storage Group that has any kind of purpose you have to have a Host, list of hosts you can find in Host List. Let’s go a little bit deeper, to have Host you can actually need to have some Initator.In this post I don’t want to go deeper, but I promise I will explain more in future posts.


OK, we have already quite a long article, I hope this give you a basic overview how to even start working with  Unisphere. Have fun and be extra careful, do not experiment with any ‘production’ VNX! 🙂

EMC VNX – Create and modify a storage pool

Once you learn the choice of creating RAID groups, and provisioning storage through LUNs created on RAID vs Storage Pool concept I’m sure you would like to learn how to create a Storage Pool. If you  don’t know what that is, try to read my previous post EMC VNX – RAID groups vs Storage Pools. What you should know? Basically what is a Storage Pool, what is the difference between Homogeneous pool and Heterogeneous pool.

 Create a pool

Creating a pool is quite simple, all you need is to provide a pool name, choose the disks and choose the protection level.

How to create Storage Pool

How to create Storage Pool

Presented figure shows an example of creating a heterogeneous storage pool with name Pool 1, and 3 disk types, with RAID5 for Flash and SAS disks, and RAID6 for NL-SAS disks.

The Scheduled Auto-Tiering box is visible only when the FAST enabler is installed and the Pool radio button is selected. Once you select that option, you will include this storage pool in the auto-tiering schedule. I bet you wonder what is in Advanced box, don’t you?

Create Storage Pool - Advanced Tab

Create Storage Pool – Advanced Tab

The Advanced tab can be selected to configure Thresholds and FAST Cache (of course if the FAST Cache enabler is present when the pool is created). Snapshot section will be available if the Snapshot enabler is loaded. As present in the printscreen, you can schedule automatically deletion of snapshots if the monitored space is above chosen threshold.
A VNX can contain one or many pools. Pools can be as large as the maximum number of drives (expect vault drives and hot spares obviously), lathough there are limits of maximum allowed drive increment. For example with VNX5300 you can create a pool with maximum of 40 drives at a time, but later you can expand this pool with another 40 drives to reach 80 disks in total.

Expanding  Pools

You can easily expand RAID Group, and Pools. To do so, you need to have extra hard drives available. Right-click on the pool, and select Expand.

Expanding Pools

Expanding Pools

The operation is simple. From the Expand Storage Pool window, select the number of disks by using the dropdown arrow. Remember the limit of creating big Pools? Depends on the VNX model you can use limited number of disks at once, for example maximum number of disks with VNX5500 is 80, so if you would like to create a pool from 120 disks you need to first create a pool using 80 disks, and then expand this pool with additional 40 disks.

Shrinking Pools

As with RAID groups, the same is with Pools, you cannot shrink the pool. To release some space you would have to completly destroy the pool.

EMC VNX – RAID groups vs Storage Pools

With EMC training I have learnt some general guidelines, that should be followed to optimize and enable good performance on a VNX Unified storage system.

Drive types

When you chose a specific drive type, you should base your choice upon the expected workload.

  • FLASH – Extreme Performance Tier – great for extreme performance.
  • SAS – Performance Tier – perfect for general performance. Usually 10k RPM or 15k RPM.
  • NL-SAS – Capacity Tier – most cost effective, for streaming, agining data and archives and backups

RAID groups

When we want to provision storage on our hard drives, first we have to create either a RAID group, or a Storage Pool. Let’s first review RAID groups.

RAID Levels

Within EMC VNX RAID groups should have a maximum count of 16 drives (which is strange, since this rule does not apply to NetApp at all!).
Choosing the correct drive type is only one step, you also have to choose a correct RAID group.

  • RAID 1/0 – this RAID group is appropriate for heavy transactional workloads with a high rate of random writes (let’s say greater than 25-30%)
  • RAID 5 – I would say this one is most common one. Works best for medium to high performance, general-purpose and sequential workloads. And it’s much more space effective, since blocks are not mirrored, and parity takes only one extra disk (distributed on all disks thru the RAID group)
  • RAID 6 – Most often used for NL-SAS. Works best with read-based workloads such as archiving and backup to disk. It provides additional RAID protection (two disk may fail in one RAID group, instead of 1 with RAID5).

As I mentioned before, RAID groups can have a maximum count of 16 drives (not with NetApp). For parity RAID, the higher the count, the higher the capacity utilization (since there is only one parity disk in RAID5, and 2 parity disks in RAID6 regardless the RAID group size).

Preffered RAID configuration

With a predominance of large-block sequential operations the following rules are most effective:

  • RAID5 has a preference of 4+1 or 8+1
  • RAID6 has a preference of 8+2 or 14+2
  • RAID1/0 has a preference of 4+4

One more tip – when creating RAID groups, select drives from the same bus if possible to boost performance (always prefer horizontal over vertical selection).

Storage Pools

A storage pool is somehow analogous to a RAID group. In few words it’s a physical collection of disks on which logical units (LUNs) are created. Pools are dedicated for use by pool (thin or thick) LUNs. Where RAID group can only contain up to 16 disks, pool can contain hundreds of disks. Because of that, pool-based provisioning spreads workloads over many resources requiring minimal planning and management effort.

Of course pool has the same level of protection against disk failure as RAID groups, simply because RAID groups are used to build up pool. In fact, during pool creation, you have to choose which RAID configuration you preffer.

Pools can be homogeneous or heterogeneous. Homogeneous pools have a single drive type (e.g. SAS or NL-SAS) whereas heterogenous pools contain different drive types. Why EMC allow us to mix different drive types in one pool? Actually it’s pretty clever, le me go a little deeper into that:

Homogeneous pools

Pools with single drive type are recommended for application with similar and expected performance requirements. Only one drive (Flash, SAS, NL-SAS) is available for selection during pool creation.

Homogeneous Storage Pools

Homogeneous Storage Pools

Picture above shows three Storage pools, one created from Flash Drives (extreme performance tier), another created form SAS drives (performance tier) and the third one created from NL-SAS drives (capacity tier)

Heterogeneous pools

As mentioned previously, heterogeneous pools can consist different types of drives. VNX supports Flash, SAS, and NL-SAS drives in one pool. Heterogeneous pools provide the infrastructure for FAST VP (Fully Automated Storage Tiering for Virtual Pools).

Heterogeneous Storage Pools

Heterogeneous Storage Pools

FAST VP facilitates automatic data movement to appropriate drive tiers depending on the I/O activity for that data. The most frequently accessed data is moved to the highest tier (Flash drives) in the pool for faster access. Medium activity data is moved to SAS drives, and low activity data is moved to the lowest tier (NL-SAS drives).