Hi,
Does anybody has any experience with e-sata on CentOS5.2?
- How fast is it? Same as an internal sata? - Does it support sata-2? - Does it "hot-plug" like a USB?
On Sun, January 25, 2009 5:02 pm, centos@911networks.com wrote:
I use one ExpressCard eSATA II controller with a laptop under CentOS 5. The controller requires reboot in order to be recognized (at least I don't know a way to make it work any other way), but the disks are hot-pluggable just like with USB. No idea how the speed compares to internal SATA.
Marko
centos@911networks.com wrote:
The 'E' just means the connector comes out the back. Otherwise it is the same as internal with the same options that depend on the controller model and driver. Most, but not all SATA controllers support hot-plug but I think it needs to be done at the drive level, not the cable to the case so the connectors can enforce the right order of connections on the power and data side.
Les Mikesell wrote:
its also a slightly different connector, they are keyed differently so you can't use a internal SATA cable in extenral eSATA jack. eSATA spec allows longer wiring, and requires better shielding.
ALL sata connectors physically have hotswap capability to support raid backplanes and such (primarily, longer ground pins), but as you said, there's software issues in recognizing new devices and enumerating them and bringing up their dev nodes.
Hi,
On Sun, Jan 25, 2009 at 17:02, centos@911networks.com wrote:
Does anybody has any experience with e-sata on CentOS5.2?
Yes.
Same as internal. Just the connector is different.
Depends on the adapter you get.
First time I got an Adaptec eSATA II RAID 1225SA and it turns out that, even though they use a standard Silicon Image 3132 (IIRC) that is supported by the sata_sil24 native driver, they ship it with a non-default PCI ID, so the default kernel in CentOS 5 does not recognize it. I opened a bug for it and I got the patch to include that PCI ID in CentOS-plus kernel, so if you use that kernel the adapter will work. Anyway, I would stay away of it if possible. http://www.adaptec.com/en-US/support/raid/sataii/AAR-1225SA/
Second time around I got one from StarTech.com, it also uses the sata_sil24 native driver, and this one works out of the box. I just had a small glitch to have it recognized by the server the first time around, which was fixed by moving it to another PCIe slot (not sure why it did not work on the first one I tried). I can recommend this one: http://www.startech.com/item/PEXESATA2-2-Port-PCI-Express-eSATA-Controller-C...
Both work with SATA II (3Gbps) and both support "hot-plug", only in some cases you may need to force scanning (with a command such as "echo 1 >/sys/class/scsi_host/hostX/scan"), I'm not sure if you have to do that always or not.
Here some information on Linux SATA drivers, very useful: http://linuxmafia.com/faq/Hardware/sata.html Stay away from those that need proprietary drivers.
I still would like to find an adapter that works with the Linux ahci driver, since that seems to be the best one, at least from information in that web page, but so far no luck finding them...
HTH, Filipe
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centos＠911networks.com -
Filipe Brandenburger -
John R Pierce -
Les Mikesell -
Marko A. Jennings