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From: shaw news on 26 Apr 2010 14:05
thx all;

wonderful info.
I will transfer the OS to single drive, probably using cheap card for
additional ports

I found the transfer from the corrupted volume to the esata WD green 5200
rpm can hit steady throughput of 1400MB/minute with the Symantec Ghost
enterprise 2.5 x64 version. the slow performance I initially quoted were
partly vista and partly small file impact.

nonetheless less imaging the 1TB disk array still takes about 13 hours!
despite there is only 0.5 TB of data. there must be a better way to taking
the boot sector along the OS partitions to redeploy to smaller drives
instead of the image all approach I used on the Symantec ghost

BTW, Paul thx for the wealth of info. Newegg have changed the web page, it
only shows image of card but not enough clue to guess what card it is,
can you tell me more?


From: Paul on 26 Apr 2010 18:24
shaw news wrote:
<<snip>>
>
> BTW, Paul thx for the wealth of info. Newegg have changed the web page, it
> only shows image of card but not enough clue to guess what card it is,
> can you tell me more?

Look for Areca brand cards. There are ones with different numbers of ports.
I didn't pick a particular one, and showed that picture, to show the DIMM
used as a cache, located on the card. I think the Areca with the most
ports on it, can handle something like 24 drives. (They make cards for SAS
and SATA drives.) I picked that brand, because they make expensive cards.
The cards use an onboard Intel processor for RAID processing and running
the cache.

Some midrange RAID cards, have three chips soldered to the card surface.
The cache on those is a bit smaller. Then, there are the cards with a DIMM
slot, and they can take more memory. The liability with having a lot of
cache RAM, is what happens in a power failure. It is best to have a UPS,
where the UPS cable that announces shutdown, is plugged into your computer.
Then, if the computer is running and unattended, Windows can shutdown
in an orderly manner, issue the cache flush, and no cached data would be lost
before the computer soft powers off.

When there is cache RAM, some cards include a battery backup, so that the
cache contents can't get lost. It is a good feature, as long as the
power to the computer is restored in time, for the cached data to
be transferred to the disks. I don't really like having batteries involved
(because you have to worry about whether, eventually, the rechargeable
batteries are dead), but that is how they do it.

For the cheapest RAID cards, you may be getting nothing more than SATA
ports, which is what your Intel chipset chip was providing. The card may
be cheap, but it really isn't providing anything you don't already have.
Just software written by a different team of software writers.

Paul


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