Pros & contras

Pros:

Reduced equipment costs. For simple projects with a single server: SAS HBA or chipset controller instead of a hardware RAID-controller; the ability to use inexpensive SATA drives that are formally not compatible with hardware RAID (for example, WD Red) instead of nearline class drives.

For projects with a single non-resilient data storage system  and high requirements for disk density we can use the following platforms: 72 disks in 4U, up to 432 Tb of raw capacity when using  6 Tb disks.

For clustered solutions: simple disk racks (SAS JBOD's) instead of expensive storages.

High performance. The solution based on Storage Spaces + SSD easily scales in bandwidth and IOPS by adding disk racks and HBA up to several million IOPS and tens of Gb/sec. The relatively low performance of conventional HDDs can be compensated by the use of tiered storage with the placement of "hot" data on the SSD and/or using the SSD to cache-write operations.

Using tiering (tiered storage) in combination with cachie-write to SSDs in Storage Spaces in most cases works more efficiently, cheaper and has large scalability limits compared to implementing SSD cache on hardware RAID-controllers (for example, LSI CacheCade or Adaptec MaxCache).

Flexible use of disk space. In Storage Spaces you can combine volumes with any level of resiliency on one disk group (in one pool) and when adding SSD to the pool with any ratio of capacity between HDD and SSD tiers and/or write-back cache capacity.

For all types of volumes (except for cluster use) tiered volumes and Dual Parity volumes Thin Provisioning is supported  - this allows us to allocate capacity only when we actually use it.

Contras:

Poor recording performance when using conventional HDDs (especially in Parity and Dual Parity). A certain type of write load (random access in small blocks concentrated in a certain area) can be easily compensated by adding SSDs as a fast tier and write-cache. But we are not be able to compensate the long linear load on the recording. So we can’t recommend using Storage Spaces, for example, in video surveillance solutions.

For budget cluster solutions built on Windows (with a similar architecture based on SAS JBOD) with a high write load we do recommend using special LSI Syncro CS RAID controllers (or similar) instead of Storage Spaces.

Limited cluster scaling. To use Storage Spaces in a cluster we need to share disks through a disk rack with 2 SAS expanders (SAS JBOD). SAS JBOD is not a separate independent storage system. Therefore, a cluster using Storage Spaces can consist of a maximum of 4 nodes (a special SAS JBOD with 4 inputs per expander is required) and in typical configurations with SAS JBOD Supermicro. A maximum of 3 nodes (or 2 when connect additional JBODs in cascade).

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