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macmesser

macrumors 6502a
Original poster
Aug 13, 2012
921
198
Long Island, NY USA
On my '09 Mac Pro I've been using a 120GB SSD for my scratch disk and plan to put it, along with my 250GB SSD boot drive, on a SATA III PCIe 2 controller card which splits 4 SATA channels between 2 SATA and 2 eSATA ports. My other HDs can stay on the system SATA II, which means I won't really be wanting to work on those drives. I also don't like to work on my boot drive. Can I save a file on my scratch disk and later move to HD when finished? Is that likely to cause a bottleneck or any other kind of IO speed hit? The 120 GB scratch disk is probably at least 2X the size it needs to be because I got it at a cheap price. Will I be OK just saving to this scratch disk or should I partition it into working and scratch? Would that have any effect?
 
On my '09 Mac Pro I've been using a 120GB SSD for my scratch disk and plan to put it, along with my 250GB SSD boot drive, on a SATA III PCIe 2 controller card which splits 4 SATA channels between 2 SATA and 2 eSATA ports. My other HDs can stay on the system SATA II, which means I won't really be wanting to work on those drives. I also don't like to work on my boot drive. Can I save a file on my scratch disk and later move to HD when finished? Is that likely to cause a bottleneck or any other kind of IO speed hit? The 120 GB scratch disk is probably at least 2X the size it needs to be because I got it at a cheap price. Will I be OK just saving to this scratch disk or should I partition it into working and scratch? Would that have any effect?
Something to check - some inexpensive "4 port" SATA+eSATA controllers are really "2 port" controllers that can be switched between SATA and eSATA - that is, either the internal ports can be active, or the external ports, but not both.

For example: https://www.neweggbusiness.com/product/product.aspx?item=9b-16-129-101
 
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Something to check - some inexpensive "4 port" SATA+eSATA controllers are really "2 port" controllers that can be switched between SATA and eSATA - that is, either the internal ports can be active, or the external ports, but not both.

For example: https://www.neweggbusiness.com/product/product.aspx?item=9b-16-129-101


Thanks for reply. You're correct, as I found out. I found a well priced ($32 US) and very versatile card (StarTech PEXESAT32) which is a true two port controller that has one SATA and 1 eSATA port. It also supports port multiplier on eSATA and hardware assisted RAID 0, RAID 1 and JBOD. On Amazon it has 4+ stars in reviews with over 300 reviews and can be found at: https://www.amazon.com/dp/B003GSGMP...olid=127NX4BUCUAGV&coliid=ISO6UOPQMASDR&psc=1

I might add that support responded quickly to my query and pointed out the appropriate product based on my intended application. Note that there is a very similar product with identical functionality, but is not Mac compatible. The PEXESAT32 does support Ubuntu and Windows in addition to Mac through 10.11. This is the card you need if you are looking to add SATA III/eSATA and you can even connect your internal boot drive to it.

With frugality I can extend greatly my computing experience, which is why I buy used Macs. This card was really hard to pass up, but I opted for a HighPoint RocketRAID 642L at 3X the cost. It has double the active ports (4) plus more robust RAID, in addition to the features of the other card. It was the availability of two internal SATA III connectors on the RR642L that caused me to pass up an excellent bargain priced card as I intend to use the two internal connectors to connect my SSD boot and scratch drives.

NOTE: I originally incorrectly stated (now corrected) that this card allows for 2 active ports in any combination of SATA/eSATA. While the Windows compatible card allows any combination, this Mac card offers 1 SATA and 1 eSATA only.
 
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I've come to really, really hate port multiplier cards. More than Trump hates freedom.

I've been replacing my Highpoint cards (although one would expect that they'd work with Sans Digital enclosures, since they're included with some.

The problem that I've been seeing is that the cards will timeout and drop all disks offline, usually triggered by higher loads. Then the problem is that the card resets, bring the disks back online, which triggers a flurry of IOs as the disks replay the logs and rebuild the volumes.

But the flurry of IOs triggers another timeout - so mid rebuild the volume drops offline again, and another rebuild starts.

I've come to the conclusion that HPT controllers are useless for host RAID (and no other controllers as well), and I have moved to LSI 3ware with BBU for RAID-5 volumes, and LSI 9207 controllers form host-based RAID-0.

I want to get rid of every HPT controller doing PM in my life. A nightmare.
 
I won't be using raid. Just thought I could take advantage of the two SATA ports. Most I would use is port multiplier, and on the particular machine I'm upgrading all I really need is ability to boot from single eSATA drive. So maybe the HPT card will work out.
 
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