Many SATA disks

[Mike Tancsa]

On 3/31/2012 6:28 PM, Daniel Feenberg wrote:
> 
> We would like to build a FreeBSD machine ourselves with many (~15) SATA
> drives, but NOT use a RAID controller. We want to be able to remove any
> drive and connect it to an ordinary motherboard SATA port and mount the
> filesystem using only the OS provided drivers and tools. I have built
> many FreeBSD systems, but never used port multipliers and don't know
> which controllers advertised as RAID controllers will support a plain
> pass-thru mode. Would anyone like to make a suggestion from actual
> experience?
> 
> The system will be used solely for archiving, so performance is not
> critical, but portability of the partitions to other systems is necessary.


We use this controller
http://www.addonics.com/products/adsa3gpx8-4e.php
connected to 3 external drive cages.  It works via the siis driver


# camcontrol devlist | egrep "ada|ulti"
<WDC WD2001FASS-00U0B0 01.00101>   at scbus0 target 0 lun 0 (ada0,pass0)
<WDC WD2001FASS-00U0B0 01.00101>   at scbus0 target 1 lun 0 (ada1,pass1)
<WDC WD2001FASS-00U0B0 01.00101>   at scbus0 target 2 lun 0 (ada2,pass2)
<WDC WD2001FASS-00U0B0 01.00101>   at scbus0 target 3 lun 0 (ada3,pass3)
<Port Multiplier 47261095 1f06>    at scbus0 target 15 lun 0 (pass4,pmp2)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus2 target 0 lun 0 (ada4,pass5)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus2 target 1 lun 0 (ada5,pass6)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus2 target 2 lun 0 (ada6,pass7)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus2 target 3 lun 0 (ada7,pass8)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus2 target 4 lun 0 (ada8,pass9)
<Port Multiplier 37261095 1706>    at scbus2 target 15 lun 0 (pass10,pmp0)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus3 target 0 lun 0 (ada9,pass11)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus3 target 1 lun 0 (ada10,pass12)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus3 target 2 lun 0 (ada11,pass13)
<WDC WD2002FAEX-007BA0 05.01D05>   at scbus3 target 3 lun 0 (ada12,pass14)
<Port Multiplier 37261095 1706>    at scbus3 target 15 lun 0 (pass15,pmp1)
<ST31000333AS SD35>                at scbus6 target 0 lun 0 (ada13,pass20)
<ST31000528AS CC35>                at scbus7 target 0 lun 0 (ada14,pass21)
<ST31000340AS SD1A>                at scbus8 target 0 lun 0 (ada15,pass22)
<WDC WD1002FAEX-00Z3A0 05.01D05>   at scbus11 target 0 lun 0 (ada16,pass23)


They are part of a zfs pool, but you could use them as individual drives.  If they are not part of some raid system, you will have of course no redundancy should a disk fail, unless you have some other plan for that.

For us, the pool is not usable if one of the drive cages fails, so its not the most reliable setup for high availability.  But its a backup server, so temporary down time should a PM fail is acceptable. Individual disks of course can be swapped out as needed.  Also, using ZFS allows us to easily add to the storage capacity for more backups or for longer snapshot retention.


	---Mike
-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   http://www.tancsa.com/