Storage

When you install DataCore SANsymphony-V (SSV), you will be asked during the setup to allow the installation of some special drivers. DataCore SANSymphony-V needs this drivers to act as a storage target for hosts and other storage servers. Usually you have three different port roles in a DataCore SSV setup:

• Frontend Ports (FE)
• Mirror Ports (MR)
• Backend Ports (BE)

Frontend (FE) ports act only in target-only mode. These ports will be disabled, if you stop a DataCore storage server. Mirror (MR) ports (can) act as target AND initiator. You can set (if you like) a mirror port to a specific mode (target or initiator), but I wouldn’t recomment this. Theoretically you can set one MR port to act as initiator, and a second to target-only mode. If the port is set to target-only, the port is also stopped when the DataCore storage server is stopped. A backend (BE) port acts as initiator for backend storage. Usually the FE ports act as target-only, the MR as target/ initiator and the BE ports as initiator-only. If you use local storage (or SAS connected), there will be no BE ports.

One of my longtime DataCore customers has started a project to replace their current DataCore storage servers and backend storage with new hardware. In opposite of the current setup, the newly installed backend storage is now FC-attached. The customer has selected Nexsan E-Series E32V, E32XV and E48V storage systems in combination with DataCore SANsymphony-V10.

Who is Nexsan?

The question should be: Who is Imation? Nexsan was founded in 1999 in Derby, England, but was aquired by Imation in December 2012. Since December 2012, Nexsan is one of Imations brands and offers, as a storage-only company, three different product lines: Assureon Secure Storage, E-Series High Density Storage and NST Hybrid Storage.

Since monday I’m helping a customer to put two HP 3PAR StoreServ 7200c into operation. Both StoreServs came factory-installed with 3PAR OS 3.2.1 MU3, which is available since July 2015. Usually, the first thing you do is to deploy the 3PAR Service Processor (SP). These days this is (in most cases) a Virtual Service Processor (VSP). The SP is used to initialize the storage system. Later, the SP reports to HP and it’s used for maintenance tasks like shutdown the StoreServ, install updates and patches. There are only a few cases in which you start the Out-of-the-Box (OOTB) procedure of the StoreServ without having a VSP. I deployed two (one VSP for each StoreServ) VSPs, started the Service Processor Setup Wizard, entered the StoreServ serial number and got this message:

Last sunday a customer suffered a power outage for a few hours. Unfortunately the DataCore Storage Server in the affected datacenter weren’t shutdown and therefore it crashed. After the power was back, the Storage Server was started and the recoveries for the mirrored virtual disks started. Hours later, three mirrored virtual disks were still running full recoveries and the recovery for each of them failed repeatedly.

There’s a world below clouds and enterprise environments with thousands of VMs and hundered or thousands of hosts. A world that consists of maximal three hosts. I’m working with quite a few customers, that are using VMware vSphere Essentials Plus. Those environments consist typically of two or three hosts and something between 10 and 100 VMs. Just to mention it: I don’t have any VMware vSphere Essentials customer. I can’t see any benefit for buying these license. Most of these environments are designed for a lifeime of three to four years. After that time, I come again and replace it with new gear. I can’t remember any customer that upgraded his VMware vSphere Essentials Plus. Even if the demands to the IT infrastructure increases, the license stays the same. The hosts and storage gets bigger, but the requirements stays the same: HA, vMotion, sometimes vSphere Replication, often (vSphere API for) Data Protection. Maybe this is a german thing and customers outside of german are growing faster and invest more in their IT.

Some days ago I talked to a colleague from our sales team and we discussed different solutions for a customer. I will spare you the details, but we discussed different solutions and we came across PernixData FVP, HP 3PAR Adaptive Optimization, HP 3PAR Adaptive Flash Cache and DataCore SANsymphony-V. And then the question of all questions came up: “What is the difference?”.

Simplify, then add Lightness

Lets talk about tiering. To make it simple: Tiering moves a block from one tier to another, depending on how often a block is accessed in a specific time. A tier is a class of storage with specific characteristics, for example ultra-fast flash, enterprise-grade SAS drives or even nearline drives. Characteristics can be the drive type, the used RAID level or a combination of characteristics. A 3-tier storage design can consist of only one drive type, but they can be organized in different RAID levels. Tier 1 can be RAID 1 and tier 3 can be RAID 6, but all tiers use enterprise-grade 15k SAS drives. But you can also mix drive types and RAID levels, for example tier 1 with flash, tier 2 with 15k SAS in a RAID 5 and tier 3 with SAS-NL and RAID 6. Each time a block is accessed, the block “heats up”. If it’s hot enough, it is moved one tier up. If it’s less often accessed, the block “cools down” and at a specific point, the block is moved a tier down. If a tier is full, colder blocks will to be moved down and hotter block have to be moved up. It’s a bit simplified, but products like DataCore SANsymphony-V with Auto-Tiering or HP 3PAR Adaptive Optimization are working this way.

Some days ago a colleague and I implemented a small 3-node VMware vSphere Essentials Plus cluster with a HP 3PAR StoreServ 7200c. Costs are always a sore point in SMB environments, so it should not surprise that we used iSCSI in this design. I had some doubt about using iSCSI with a HP 3PAR StoreServ, mostly because of the performance and complexity. IMHO iSCSI is more complex to implement then Fibre Channel (FC). But in this case I had to deal with it.

Sometimes you have to update the OS of your DataCore Storage Server, or the server is crashed and you have to reinstall it. In both cases, a configuration backup is the starting point. The procedure remains the same, regardless if it’s an update or a reinstall after a server crash:

• Install Windows Server OS
• Copy configuration backup file to C:\Program Files\DataCore\SANsymphony\Recovery
• Install DataCore SANsymphony-V

Take a backup

You can take the configuration backup on different ways:

NetApp has offered Data ONTAP for some time in two flavours:

• 7-Mode
• Clustered Data ONTAP (cDOT)

With cDOT, NetApp has rewritten ONTAP nearly from scratch. The aim was to create an Storage OS, that leverages scale-out architecture and storage virtualization techniques, as well as providing non-disruptive operations. NetApp has needed some release cycles to get cDOT at that point, where it provides all features that customers know from 7-Mode. With Data ONTAP 8.3, NetApp has reached this point. Even Metrocluster is now supported. That’s a huge improvement and I’m glad that NetApp has made it. But NetApp wasted no time in cutting off old habits: With ONTAP 8.3, 7-Mode is no longer offered. Okay, no big deal. Customers can migrate from 7-Mode to cDOT. Yes, indeed. But it’s not that easy as you maybe think.

A VMware vSphere cluster is nothing without shared storage. Most of the functions, like VMware HA or VMware vMotion (okay, vMotion is possible without shared storage), can only be used with a shared storage. The servers in my lab have Fibre Channel Host Bus Adapters (HBA), but buying an old and cheap Fibre Channel storage system wasn’t an option in my case. This left two options when choosing the right storage protocol: iSCSI or NFS. I tried to virtualize the local storage in my ProLiants with the HP StoreVirtual VSA and DataCore SANsymphony-V, but both were too complex for my needs and a lab environment. Because of this I decided to move the local storage into a small storage system and use iSCSI or NFS. I searched for a while for a suiteable system until Chris Wahl started blogging about the Synology DS414slim.