Dell Storage SC9000 review
Dell SC9000 adds deduplication and brings all-flash costs to an all-time low
Dell is on a mission to bring all-flash storage to the masses as its flagship SC9000 array delivers the lowest costs around. Its latest SC Operating System 7 (SCOS 7) also introduces plenty of new features including intelligent data reduction, storage QoS and unification with Dell's PS arrays.
The SC9000 controller comprises two PowerEdge R730 servers equipped with dual 3.2GHz E5-2667 v3 Xeons and 256GB of system memory. Each uses a cache card linked over fibre GBICs where all cache mirroring is carried out automatically using their 4GB of battery protected NVRAM.
The SCOS software runs on an internal SSD and storage shelves are attached using dual-port 12Gbps SAS expansion cards. Storage potential is massive as the SC9000 currently supports up to 960 SSDs and HDDs with a future firmware upgrade expected to push this to 1,024 drives and beyond.
Expansion shelves include the 12-bay and 24-bay SC400 and SC420 12Gbps SAS units plus the 84-bay SC280 which supports low-cost NL-SAS drives. Data port options are plentiful with Dell offering 10GbE copper or SFP+, FCoE or 8/16Gbps FC HBAs with 25GbE coming soon.
The SC9000 controllers have a high expansion potential and plenty of data port choices
Storage Manager and tiers
Dell's new HTML5-based Storage Manager (DSM) 2016 R2 has a well-designed interface which we found makes light work of storage configuration. A key feature is a unification as it can manage all SC, PS and FS appliances from one interface.
DSM supports VMware VVOLs and, more importantly, cross-platform replication. This is inclusive so you can now replicate volumes between PS and SC appliances at no extra cost.
Dell's auto-tiering migrates data across up to three tiers dependent on access frequency and the SC9000 supports triple layer cell (TLC) SSDs as well as SLC and MLC SSDs. Whichever you choose, the SC9000 allows businesses to use fewer SSDs to get better performance than an expensive box of SAS drives.
This makes flash storage more affordable with Dell claiming record-breaking costs of less than $0.45/GB with data reduction applied. Dell is so confident that SSDs are the way forward that its maintenance contract includes free replacement of units that fail in the warranty period.
The new DSM simplifies storage configuration and can manage all SC, PS and FC appliances
The SC9000 automates tier creation by categorising drives by their type although you can pin specific types to one tier. For testing, we used an all-flash array comprising 22 800GB SLC SSDs and 42 1.9TB MLC SSDs placed in the first and second tiers.
Storage Profiles determine which tiers data should reside on and how data progression is managed. Dell provides a range of predefined profiles and includes options for flash-optimised and standard storage types.
RAID array creation is also automatic as the SC9000 selects them to suit each tier with options for RAID0, 5, 6, 10 and dual-mirrored arrays. Physical storage is amalgamated into a single Disk Folder pool and we used the Storage Manager to create virtual volumes within it.
Data tiering doesn't occur in real-time as you create Storage Profiles to determine when this is run. By default, the profile runs data progression jobs at 19:00 every evening but you can change the schedule to suit and run them as often as every five minutes.
Deduplication and compression are applied to selected volumes with scheduled data progression jobs
Deduplication and QoS
Profiles also apply deduplication and it can be enabled globally at the controller level or on selected volumes. It's a simple process as you can turn it off, enable compression only or have deduplication and compression.
Dell's deduplication uses the standard method of breaking data streams into 4KB chunks and creating hashes for each one. It requires a minimum of six SSDs to store its hash dictionary and is controlled from the same profile schedule as used to manage data progression.
Quality of service (QoS) profiles can be applied to volumes to limit available bandwidth. We found them easy to create and could apply limits for either IOPS or MB/sec or both together.
We could enter a latency threshold value and receive an alert if this was breached. You can also apply one QoS profile to multiple volumes using a group policy.
QoS profiles apply limits on volumes for IOPS or MB/sec and can keep an eye on latency
We tested performance with two PowerEdge R720 rack servers running Windows Server 2012 R2 and equipped with QLogic dual-port 16Gbps FC adapters. With one server logged onto an all-flash virtual volume over a 32Gb/sec dual MPIO FC link, Iometer reported excellent raw random read and write rates of 24.6Gb/sec and 24.5Gb/sec.
With two servers, we saw Iometer report an impressive cumulative raw read throughput of 45Gb/sec.
We tested maximum read IOPS with a small 4KB request size and saw one server return 180,000 IOPS which ramped up to 360,000 with two servers showing no contention for resources.
We then tested with our Iometer database workload and saw it report a top throughput of 150,000 IOPS for one server. Running the workload on two servers saw a cumulative throughput of 300,000 IOPS.
DSM also provides a slick web UI which can monitor all your Dell storage arrays
We found Dell's automated tiered storage takes the strain out of storage management and the new DSM console makes configuration and provisioning even easier. Snapshots and thin provisioning are all standard features and enterprises can now manage all their Dell arrays from the same interface. All-flash performance is beyond reproach and the competition will have a tough job matching Dell's low storage costs.
The Storage SC9000 delivers an impressive enterprise feature set and teams up automated tiered storage and data reduction with a super performance and low costs for all-flash arrays
Dual controllers each with the following:
Chassis: 2U rack
CPU: 2 x 3.2GHz E5-2667 v3 8-core Xeon
Memory: 256GB DDR3
Cache memory: 4GB NVRAM and BBU
Storage: Up to 960 SSDs or HDDs supported
Array support: RAID 0, 5, 6, 10 and 10 DM
Power: 2 x 1100W hot-plug PSUs
Expansion: 7 x PCI-Express slots (6 free)
Software: Dell Storage Center OS 7
Management: Dell Storage Manager 2016 R2
Warranty: 3yrs Co-Pilot on-site 24/7 NBD 4hr response
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