On Wed, 31 Mar 2004, , wrote:
> Hi there. Just wondering if anybody's had any experiences with any of
> the 3ware ATA RAID cards with Solaris. Thanks.
No Solaris x86 drivers. Sorry.
PS: I'd love to be able to build a disk based backup server based on the
3Ware RAID controllers, Serial ATA drives (Maxtor or IBM high capacity
SATA drives) and Solaris x86. Tape based backup is becoming less desirable
over time..... especially when you consider the lower reliability of tape
based systems - IOW, you only find out there's a problem with your tape
based system when it's necessary to restore a system from tape. By that
time it's too late to fix the ("broken") tape drive or the overworked
(aka "broken") tape cartridges.
The other advantage of disk based backup systems, is the superior "time to
restore" factor. An often overlooked aspect of backup systems is the time
it takes to restore them. For example, if you have a system that failed
catastrophically and it's a production system, you have 2 factors to
consider: 1) the cost, to your business, of this system being down and 2)
the time to recover this system from a worst case data loss perspective.
With todays commodity hardware, it's not too expensive to maintain a
standby server and associated infrastructure; but nobody wants to go to a
meeting and tell upper management that it'll take N *hours* to
reconfigure/restore a working system from backup data sources. In many
cases, this simply comes down to a "time to restore" scenario; and in this
scenario, time to restore is catagorized by random access time and data
From this perspective it's easy to justify the cost of a near term, disk
based backup system. Tape based systems are beginning to look like
Another point regarding tape based systems that I'd like to present: In
many cases, tape based systems need to stream continueously in order to
maintain their rated xfer rates. Now think about this for a minute...
Lets say you have a tape based system that supports 20Mb (bytes not bits)
per Second. I can hear many readers already saying "hey .. 20Mb/Sec ..
that's way too slow". And this tape based system backs up multiple systems
via ethernet (network) connections and supports compression. Nothing
unusual about this configuration... right? So your tape drive supports
20Mbs/Sec and your average compression ratio is 2:1. OK? So now you need
your network to support a *continuous* rate of at least 40Mb/Sec to keep
your 20Mb/Sec (streaming) tape drive writing useful data. If you're not
running gigabit ethernet you're SOL! What about the case, which is not
unusual, where you have a snitload (?? typo) of files, for example, XML
files or /usr/include/*.h, that'll typically compress 5 to 1 or 6:1.
Well, in this case, with a 20Mb/Sec tape drive, your network needs to be
able to deliver 100Mb/Sec or 120Mb/Sec, sustained, to keep that tape drive
When most streaming tape drives can't sustain enough data they simply write
a stream of "0"s to the tape for a given period of time; rather than
stopping the tape, repositioning it to the point where it "ran out of data"
and starting it in streaming mode again. So you wonder why your $****
(read expensive) tape based system is not giving you the Mb/Sec backup rate
Disk based backup system don't suffer from these limitations. When they
run out of data, they simply stop. When they get multiple streams of data
from multiple data sources, they simply deal with it.. as we've come to
expect from Unix based filesystems.
So, my bottom line point is, disk based backup systems make a lot of sense.
1) don't write useless streams of "0"s if they run out of data
2) they easily deal with multiple sources of data simultaneously
3) the can easily provide > 100Mb/Sec when it's time to restore
4) provide higher data reliability than tape based systems
5) easily handle requests for random data without having to reposition like
tape based systems have to
6) provide higher reliabilty than tape and fail immediately if there's a
In most cases, hardware based RAID-5 disk systems provide ideal backup
services. They are not very efficient at writing data, but really
fast/efficient when it comes to reading data...
I think that it would be very "helpful" if Sun offered a near term,
commodity disk based, backup system for its customers. This could
easily be accomplished with 3Ware based hardware and commodity SATA disk
drivers and Solaris x86.
In the meantime you know that your only alternative involves the "L" word
based OS.... :(
Al Hopper Logical Approach Inc, Plano, TX. al@...
Voice: 972.379.2133 Fax: 972.379.2134