We have a number of Sun J4200 SAS JBOD arrays which we have multipathed using 
Sun's MPxIO facility. While this is great for reliability, it results in the 
/dev/dsk device IDs changing from cXtYd0 to something virtually unreadable like 
"c4t5000C5000B21AC63d0s3".

Since the entries in /dev/{rdsk,dsk} are simply symbolic links anyway, would 
there be any problem with adding "alias" links to /devices there and building 
our zpools on them? We've tried this and it seems to work fine producing a 
zpool status similar to the following:

...
NAME        STATE     READ WRITE CKSUM
vol01       ONLINE       0     0     0
  mirror    ONLINE       0     0     0
    top00   ONLINE       0     0     0
    bot00   ONLINE       0     0     0
  mirror    ONLINE       0     0     0
    top01   ONLINE       0     0     0
    bot01   ONLINE       0     0     0
...

Here our aliases are "topnn" and "botnn" to denote the disks in the top and 
bottom JBODs.

The obvious question is "what happens if the alias link disappears?". We've 
tested this, and ZFS seems to handle it quite nicely by finding the "normal" 
/dev/dsk link and simply working with that (although it's more difficult to get 
ZFS to use the alias again once it is recreated).

If anyone can think of anything really nasty that we've missed, we'd appreciate 
knowing about it. Alternatively, if there is a better supported means of having 
ZFS display human-readable device ids we're all ears :-)

Perhaps an MPxIO RFE for "vanity" device names would be in order?
-- 
This message posted from opensolaris.org
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

Reply via email to