Nimble Wants To Be King of the CASL

Nimble Storage is an iSCSI hybrid storage array but I think you could almost call it an appliance. They have taken a page out of the Equallogic play book with ease of use management and all the features are included. The company being founded and run by storage industry veterans from NetApp and Data Domain offer the best of those companies into arrray as well. Optimized writes with thier file system called CASL (Cache Accelerated Sequential Layout) and instant high performance compression with there Data Domain background. Nimble Storage is pegging thier CS Storage line as storage, backup and DR. Below is some information that was presented during the Saskatoon VMUG


Being a new company the get the benfits of not having legacy issues to deal and has allowed them to use today’s multi-core CPUs. The multi-core CPUs and thier natively supported variable block length all them to achiveve compression without suffering the cost of performance. I am told the current controllers on the CS line have two slots for CPU’s but they are only currently using one. It looks like they have planned for some future growth.

The flow of date on the storage array:

    Data Comes into NVRAM amd is acknowledged(72 Hour Battery backed)

    Data Moves to 12G of DRAM and CRC check sums that ensures application integrity.The Data is LZ compressed 2-4X

    CASL writes sequential Stripes to SSD & SATA based on data characteristics and ensures no white space

    SSDs are 100% cache for Reads

A copy of all active or “hot” data (and even “semi-active” data) is held in the large flash layer, enabling very fast random read performance. CASL’s index tracks hot data blocks in real time, adapting to hot spot and application workload changes in a real time fashion. The flash works a JBOD since all the writes are comitted. This is great feature since you get use all of the disk lowering the total cost.


The CASL snapshots stores compressed, incremental snapshot data on high capacity disk. The are positioning the arrays to also removed the need for backup due to having 60-90 days of snapshots on the array with not taking up much space. I know as old Equallogic customer this was a big problem in the past. I would say NetApp if good at this today. They also want you to pair it with another CS array to provide compressed, deuped replication. The replication is only asynchronous for right now but they noted you could can replicate as often as you want to a second system.


You can have 6 1 Gb\s connections (4 for workload, 1 for target discovery and 1 for management). You also have the option of 2 1 GB for target discovery and management with 2 10 Gb\s connections.N imble arrays come with dual (redundant), hot swappable controllers.

Some Features I liked:

Perofmance Policies:
The ability to easily manage and match your applications to optimize the experince. For example the Exchange log policy would not cache any of the data.

VM consistent instant snapshots, by coordinating with Microsoft VSS and VMware APIs

vCebter plug-in that allows for zero copy

Nimble mentioned only needing 12 disks to achive 20,000 exchange mailboxes

Nimble works with VMware SRM

Thoughts to think about:

What happens when you want to just to add capacity? I got into the pickle with other vendors.

Lots of IP invested into the file system for speed. What happens in 5+ year when could be all SSD?

Would be great when the cluster nodes together to you the DRAM as one single shared Cache

VDI numbers per appliance seemed low, look to another blog post for information directly related to this.

Thanks to Nimble Storage for sponsoring the Saskatoon VMUG. I look forward to seeing how your company grows in 2012.

Nimble Storage VDI Benchmarking by Dan Brinkmann:


  1. First – “CASL writes sequential Stripes to SSD & SATA”

    and then “SSDs are 100% cache for Reads”

    Don’t get it.. can you please explain?



  1. […] More information about Nimble Storage was also written up by a fellow BriForum 2011 Chicago speaker Dwayne Lessner here: […]

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