Storage spaces - SAS vs SATA


  • I need to deploy a very large (100TB+) file server to support 15-20 video editing workstations, on a very limited budget. Uptime requirements are not high - it'll serve nine-to-five users, so if I need to reboot or shut down for maintenance after 5 PM, nobody will care. Even if it does go down in the middle of the day, it's still not a big deal as long as it is recovered within a reasonable timeframe. Therefore, I'm looking at using a single file server node rather than a cluster, and either Intel JBOD2312S2SP or Supermicro 847E26-RJBOD1 DAS shelves. Using SATA drives, such as Seagate NAS series, or Western Digital Red, as opposed to Seagate Constellation ES or Western Digital RE NL-SAS drives will provide significant cost savings, and if I add an SSD tier, the differences are huge - Intel DC S3500 series are very affordable, while even the cheapest SAS SSDs cost thousands per unit, but the question is, what are the trade-offs? I know I will lose clustering support, but what about MPIO? For example, if I use the Intel JBOD boxes, get eight of them, populate each with 8x4TB SATA HDDs and 4x80GB SATA SSDs, then daisy chain them into two groups of four, and use two dual-port SAS HBAs to connect a cable (from different HBAs) to both ends of each chain, will the resulting configuration use all four SAS ports to access the drives, thus providing shelf and HBA redundancy? An HBA loss will cut off one of the loop ends, while a shelf loss (for instance, dead expander) will break it in the middle - will it gracefully recover with SATA drives, or do I need dual-port SAS drives for that? Are there any other caveats with SATA HDDs and SSDs that I need to be aware of?

    • Edited by Barmaglot Saturday, May 10, 2014 7:16 PM typo
    Saturday, May 10, 2014 7:15 PM

All replies

  • SAS give away more IOPS but transfer rate has very little to do with interface so SATA for video edit workload dominated with sequential reads and writes definitely makes sense. If you don't have any plans to deploy Clustered Storage Spaces (they need dual-port SAS, converters do a bad job...) then stick with SATA-all-around and you'll be fine. MPIO is out just like enclosure awareness. Make sure you connect every enclosure to own port (don't chain them).

    StarWind VSAN [Virtual SAN] clusters Hyper-V without SAS, Fibre Channel, SMB 3.0 or iSCSI, uses Ethernet to mirror internally mounted SATA disks between hosts.

    Sunday, May 11, 2014 2:02 AM
  • What do you mean by "MPIO is out just like enclosure awareness"? The shelves themselves support SES - do you mean that installing SATA drives into SAS enclosures with SAS expanders and SAS backplanes disables SES? This would mean that there will also be no way to identify failed drive slot locations, and enclosure loss protection would not be available, correct? Also, I'm not sure how to read this document - it seems to imply that MPIO is possible for single-port backplanes (example 3), and flat out states that cascading enclosures up to four deep is supported.

    Edit: Just to be completely clear, the topology I have in mind is this:

    The two SAS HBAs would be located in the same server. The idea is that in case of an HBA, cable, or enclosure (expander/backplane) failure, the system would stay up. Will this work with SATA drives (WD Red series, Intel DC S3500), or will it require SAS/NL-SAS (Seagate Constellation ES, Seagate Pulsar)?

    • Edited by Barmaglot Sunday, May 11, 2014 7:02 AM Added diagram
    Sunday, May 11, 2014 3:27 AM