05b92097cb
arrangement that has no intrinsic internal knowledge of whether devices it is given are truly multipath devices. As such, this is a simplistic approach, but still a useful one. The basic approach is to (at present- this will change soon) use camcontrol to find likely identical devices and and label the trailing sector of the first one. This label contains both a full UUID and a name. The name is what is presented in /dev/multipath, but the UUID is used as a true distinguishor at g_taste time, thus making sure we don't have chaos on a shared SAN where everyone names their data multipath as "Fred". The first of N identical devices (and N *may* be 1!) becomes the active path until a BIO request is failed with EIO or ENXIO. When this occurs, the active disk is ripped away and the next in a list is picked to (retry and) continue with. During g_taste events new disks that meet the match criteria for existing multipath geoms get added to the tail end of the list. Thus, this active/passive setup actually does work for devices which go away and come back, as do (now) mpt(4) and isp(4) SAN based disks. There is still a lot to do to improve this- like about 5 of the 12 recommendations I've received about it, but it's been functional enough for a while that it deserves a broader test base. Reviewed by: pjd Sponsored by: IronPort Systems MFC: 2 months
28 lines
362 B
Makefile
28 lines
362 B
Makefile
# $FreeBSD$
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SUBDIR= geom_bde \
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geom_bsd \
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geom_cache \
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geom_ccd \
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geom_concat \
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geom_eli \
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geom_fox \
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geom_gate \
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geom_journal \
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geom_label \
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geom_mbr \
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geom_mirror \
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geom_multipath \
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geom_nop \
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geom_pc98 \
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geom_raid3 \
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geom_shsec \
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geom_stripe \
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geom_sunlabel \
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geom_uzip \
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geom_vinum \
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geom_vol_ffs \
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geom_zero
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.include <bsd.subdir.mk>
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