Support for hybrid enclosures
ESS supports hybrid enclosures that comprise four or two enclosures containing only hard disk drives (HDDs) and one or two enclosures of only solid state drives (SSDs).
- GH14S
- 1 2U24 (SSD) and 4 5U84 (HDD) enclosures
GH14S recovery groups (RGs)
Each of the two GH14S RGs have a 12-disk SSD user declustered array (DA) and a 167-disk HDD user DA.
- GH24S
- 2 2U24 (SSD) and 4 5U84 (HDD) enclosures
GH24S recovery groups
Each of the two GH24S RGs have a 24-disk SSD user DA and a 167-disk HDD user DA.
- GH12S
- 1 2U24 (SSD) and 2 5U84 (HDD) enclosures
GH12S recovery groups
Each of the two GH14S RGs have a 12-disk SSD user DA and an 83-disk HDD user DA.
Hybrid enclosure cabling information
Hybrid enclosure support in gssgenvdisks
The gssgenvdisks command can detect hybrid enclosures. In case of hybrid enclosures, the gssdgenvdisks command requires two declustered arrays (DAs). One DA comprises HDDs only and the other one comprises SSDs only.
gssgenvdisks provides a default placement policy in case hybrid enclosures are used. According to this policy, any data vdisk is placed on the DA which is composed of HDDs only and any metadata vdisk is placed on the DA which is composed of SSDs only.
# gssgenvdisks --create-vdisk --create-nsds --create-filesystem --verbose \
--contact-node essio41 --filesystem-name gpfs0 --reserved-space-percent 1
...
...
# mmlsvdisk
declustered block size
vdisk name RAID code recovery group array in KiB remarks
------------------ --------------- ------------------ ----------- ---------- -------
rg_io41_ce_Data_16M_2p_1 8+2p rg_io41-ce DA1 16384
rg_io41_ce_Data_16M_2p_2 8+2p rg_io41-ce DA1 16384
rg_io41_ce_MetaData_1M_3W_1 3WayReplication rg_io41-ce DA2 1024
rg_io41_ce_loghome 4WayReplication rg_io41-ce DA1 2048 log
rg_io41_ce_logtip 2WayReplication rg_io41-ce NVR 2048 logTip
rg_io41_ce_logtipbackup Unreplicated rg_io41-ce SSD 2048 logTipBackup
rg_io42_ce_Data_16M_2p_1 8+2p rg_io42-ce DA1 16384
rg_io42_ce_Data_16M_2p_2 8+2p rg_io42-ce DA1 16384
rg_io42_ce_MetaData_1M_3W_1 3WayReplication rg_io42-ce DA2 1024
rg_io42_ce_loghome 4WayReplication rg_io42-ce DA1 2048 log
rg_io42_ce_logtip 2WayReplication rg_io42-ce NVR 2048 logTip
rg_io42_ce_logtipbackup Unreplicated rg_io42-ce SSD 2048 logTipBackup
You can override the default vdisk placement policy used in case of a hybrid enclosure system, by using the --use-only-da option. If the --use-only-da option is used, only the specified DA is considered for the vdisk creation. If the system is a hybrid enclosure and there are multiple DAs, the DAs available in the recovery group are not considered except for the one specified with the --use-only-da option.
You can create vdisks on other DAs using the BM Spectrum Scale RAID command.