Micron S600DC SAS SSDs are certified for use with CloudByte ElastiStor

While CloudByte ElastiStor has compatibility with a wide range of enterprise-class SSDs to its credit, it adds Micron SAS SSDs as the latest entry to this list. Micron is a world leader in nonvolatile media design, manufacturing and qualification/testing. Micron SSDs deliver enterprise-hardened reliability and dependability of SAS, along with unmatched flexibility in terms of capacity and endurance options to meet any workload. Its critical features include dual-port redundancy, encryption, counterfeiting measures, secure erase capabilities and 12Gbps support. The disks also incorporate Micron’s proprietary SSD architecture enhancements that include RAID-like protection for NAND components and reduced peak latency.

The list of certified disks include those in the Micron S600DC family — from S610DC through S655DC. The table below provides a brief description of these disks.

CERTIFICATION TESTS

The Micron SSDs were tested in setups mimicking the standard ElastiStor production deployments, where they were used in a shared disk configuration, consumed by both nodes of a HA group (thereby subjected to SCSI3 persistent reservation commands, both for actual reservation as well as monitoring purposes). The disks were also configured with dual paths, with enclosures being accessed via separate SAS switches. They were used in their capacity as

(a) Members of High performance data pools (all supported ZFS RAID levels).

(b) Read (L2ARC) /Write (SLOG) cache devices attached to high-capacity NLSAS pools.

The SSDs were subjected to various real-world application workloads emulated using popular I/O tool vdbench. These included: OLTP, DB backup/restore, webserver, mailserver, VDI, media streaming, and HDFS workloads. Faults injected under loaded conditions included: Disk, enclosure, SAS switch, card, node failures and power-cycle tests. The performance and reliability of the disks as measured during above tests were found to be in tune with expectations.

Manageability Services on the ElastiStor nodes work seamlessly with the disks to collect and display device-specific information and to perform ZFS specific disk handling (write/clear pool labels, turn state offline/online). The SSDs were also tested across Cloudbyte supported SES 2.0 enclosures such as Dell and SuperMicro.

Provided below is a schema of the deployment diagram used for the Micron SSD certification tests.

DISK FIRMWARE UPGRADE

Micron SSD firmware upgrade is essentially online in nature with no data unavailability, though the disk needs to be taken offline for the duration of the upgrade (except if the pool of which the disk is a part is a striped zpool, which is not a CloudByte recommended configuration). In case of data groups, I/O during this period can continue on remaining disks. In case of cache devices, the pool will operate without secondary caching for a brief period (typically takes a minute). The disk firmware package is available as a load file (.lod) from Micron as part of periodic firmware releases.

The following steps are recommended by CloudByte to ensure a smooth upgrade process (executed on the ElastiStor command shell). The steps will be automated through a UI function in subsequent releases.

• Perform camcontrol rescan bus <bus number> followed by camcontrol devlist — to identify the micron disks attached to the HBA and its current firmware version.
• Mark the disk for maintenance if in a RAID group/Storage pool (perform zpool offline of device) to avoid corruption/errors.
• Perform sg_write_buffer with buffer_id=0, mode=0x7, input_file=.lod package and device=”da” name.

Note: In case error is encountered while running above, read the file in multiple parts by specifying starting offset and length to read (& flash) as shown below:

sg_write_buffer — id=0 — in=Micron_M016_SDND.LOD — mode=0x7 — specific=0 — offset=0 — length=8192 -vvvv da1

sg_write_buffer — id=0 — in=Micron_M016_SDND.LOD — mode=0x7 — specific=0 — offset=8192 — skip=8192 — length=8192 -vvvv da1

sg_write_buffer — id=0 — in=Micron_M016_SDND.LOD — mode=0x7 — specific=0 — offset=1851392 — skip=1851392 — length=8192 -vvvv da1

• Bring the disk online in the RAID group/Storage pool using the Elasticenter UI (perform zpool online of device).
• Wait for the reconstruction task to complete.
• Perform camcontrol rescan bus <bus number> followed by camcontrol devlist — to verify that the disk firmware has been upgraded.

RECOMMENDED SETTINGS AND BEST PRACTICES

Here are a few settings that were identified during the tests which will ensure greater reliability and better performance from the Micron disks on CloudByte ElastiStor

• Disable WCE on the Micron SSD (Use the command below on the ElastiStor shell. This step will be automated in subsequent releases).

echo “WCE: 0” | camcontrol modepage /dev/da1 -m 0x08 -e

• Set the following sysctls to disable disk cache flush calls post completion of every write, especially if the Micron SSD is used as ZIL/SLOG.

vfs.zfs.vdev.bio_flush_disable=1

vfs.zfs.cache_flush_disable=1

vfs.zfs.zil_cache_flush_disable=1

• While making a choice between available micron disks, use the model with the higher endurance factor as the ZIL/SLOG disk. S655DC disks have the highest endurance factor among all models in the family with 25 DWPD.
• The S.M.A.R.T utility on CloudByte ElastiStor, i.e. smartctl, may sometimes need an additional flag ‘–T permissive’ to extract disk details, due to non-implementation of a few optional smart options (or issues with the interface to view the same).

Details about Micron SSD technology and S600 family of disks in particular can be found here :

https://www.micron.com/products/solid-state-storage/advantages-micron-ssds-bring-to-data-centers

https://www.micron.com/products/solid-state-storage/product-lines/s600dc#/

CONCLUSION

The performance tests and functionality tests of ElastiStor were passed successfully on Micron SAS SSDs. The HCL list is updated here,

http://www.cloudbyte.com/support/hardware-compatibility-list/