1. YES, Native Raid can recover from various failures: drawers, cabling,
controllers, power supplies, etc, etc.
Of course it must be configured properly so that there is no possible
single point of failure.
hmmm, this is not really what i was asking about. but maybe it's easier
in gss to do this properly (eg for 8+3 data protection, you only need 11
drawers if you can make sure the data+parity blocks are send to
different drawers (sort of per drawer failure group, but internal to the
vdisks), and the smallest setup is a gss24 which has 20 drawers).
but i can't rememeber any manual suggestion the admin can control this
(or is it the default?).
I got the impression that GNR was more in line with the Engenio dynamic
disk pools
well, it's uses some crush-like placement and some parity encoding
scheme (regular raid6 for the DDP, some flavour of EC for GNR), but
other then that, not much resemblence.
DDP does not give you any control over where the data blocks are stored.
i'm not sure about GNR, (but DDP does not state anywhere they are drawer
failure proof ;).
but GNR is more like a DDP then e.g. a ceph EC pool, in the sense that
the hosts needs to see all disks (similar to the controller that needs
access to the disks).
http://www.netapp.com/uk/technology/dynamic-disk-pools.aspx
http://www.dell.com/learn/us/en/04/shared-content~data-sheets~en/documents~dynamic_disk_pooling_technical_report.pdf
That is traditional RAID sucks with large numbers of big drives.
(btw it's one of those that we saw fail (and get recovered by tech
support!) this week. tip of the week: turn on the SMmonitor service on
at least one host, it's actually useful for something).
stijn
JAB.
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