Hi Lance,
We are doing it with beegfs (mdadm and NVMe drives in the same HW.) For
GPFS have you updated the nsddevices sample script to look at the mdadm devices
and put it in /var/mmfs/etc?
BTW I'm interested to see how you go with that configuration.
Cheers,
Greg
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Lance Nakata
Sent: Friday, November 16, 2018 1:07 PM
To: [email protected]
Cc: Jon L. Bergman <[email protected]>
Subject: [gpfsug-discuss] How to use RHEL 7 mdadm NVMe devices with Spectrum
Scale 4.2.3.10?
We have a Dell R740xd with 24 x 1TB NVMe SSDs in the internal slots. Since
PERC RAID cards don't see these devices, we are using mdadm software RAID to
build NSDs. We took 12 NVMe SSDs and used mdadm to create a 10 + 1 + 1 hot
spare RAID
5 stripe named /dev/md101. We took the other 12 NVMe SSDs and created a
similar /dev/md102.
mmcrnsd worked without errors. The problem is that Spectrum Scale does not see
the /dev/md10x devices as proper NSDs; the Device and Devtype columns are blank:
host2:~> sudo mmlsnsd -X
Disk name NSD volume ID Device Devtype Node name
Remarks
---------------------------------------------------------------------------------------------------
nsd0001 864FD12858A36E79 /dev/sdb generic
host1.slac.stanford.edu server node
nsd0002 864FD12858A36E7A /dev/sdc generic
host1.slac.stanford.edu server node
nsd0021 864FD1285956B0A7 /dev/sdd generic
host1.slac.stanford.edu server node
nsd0251a 864FD1545BD0CCDF /dev/dm-9 dmm
host2.slac.stanford.edu server node
nsd0251b 864FD1545BD0CCE0 /dev/dm-11 dmm
host2.slac.stanford.edu server node
nsd0252a 864FD1545BD0CCE1 /dev/dm-10 dmm
host2.slac.stanford.edu server node
nsd0252b 864FD1545BD0CCE2 /dev/dm-8 dmm
host2.slac.stanford.edu server node
nsd02nvme1 864FD1545BEC5D72 - -
host2.slac.stanford.edu (not found) server node
nsd02nvme2 864FD1545BEC5D73 - -
host2.slac.stanford.edu (not found) server node
I know we can access the internal NVMe devices by their individual /dev/nvmeXX
paths, but non-ESS-based Spectrum Scale does not have built-in RAID
functionality. Hence, the only option in that scenario is replication, which
is expensive and won't give us enough usable space.
Software Environment:
RHEL 7.6 with kernel 3.10.0-862.14.4.el7.x86_64 Spectrum Scale 4.2.3.10
Spectrum Scale Support has implied we can't use mdadm for NVMe devices. Is
that really true? Does anyone use an mdadm-based NVMe config? If so, did you
have to do some kind of customization to get it working?
Thank you,
Lance Nakata
SLAC National Accelerator Laboratory
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