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Chris Gerhard's Weblog
Thursday September 03, 2009
Improved sd.conf format
Editing sd.conf has always been somewhat difficult thanks to it not being a documented interface and that the interface was never inteded to be exposed and it was even architecture specific. Fortunately Micheal documented it, which meant that it was known even if syntax remained obscure.
However after ARC case 2008/465 was approved and the changes pushed as part of bug 6518995 you can now use more a human readable syntax1:
sd-config-list=
"ATA VBOX HARDDISK", "disksort:false";
As it turns out the “disksort”2 option along with the thottle-max and throttle-min are the ones I most often want to tune.
Here is the current list of tunables lifted straight from the ARC case.
|
Tunable_Name |
Commitment |
Data_Type |
|
cache-nonvolatile |
Private |
BOOLEAN |
|
controller-type |
Private |
UINT32 |
|
delay-busy |
Committed |
UINT32 |
|
disksort |
Private |
BOOLEAN |
|
timeout-releasereservation |
Private |
UINT32 |
|
reset-lun |
Private |
BOOLEAN |
|
retries-busy |
Private |
UINT32 |
|
retries-timeout |
Committed |
UINT32 |
|
retries-notready |
Private |
UINT32 |
|
retries-reset |
Private |
UINT32 |
|
throttle-max |
Private |
UINT32 |
|
throttle-min |
Private |
UINT32 |
1This reminds me of the change to /etc/printcap that allowed you to specify the terminal flags as strings rather than as a bitmap. All the mystery seemed to be removed!
2While I used disksort as an example for this case I can't think of any reason why you would have it enabled for a virtual disk in VirtualBox.
( Sep 03 2009, 04:49:40 PM BST ) Permalink Trackback
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I've always wondered, but have never seen an example of, whether you could do something like this with the sd-config-list/ssd-config-list:
sd-config-list=
"VENDOR1 PRODUCT1","sd-ver1-array1",
"VENDOR2 PRODUCT2","sd-ver1-array2";
<.. define sd-ver1-array1 and sd-ver1-array2 ..>
Which would be handy if, for instance, you were going to attach an EMC DMX and an HDS TagmaStor to the same host, and wanted to configure them differently.
Posted by Gordon Marler on September 04, 2009 at 03:55 PM BST #
Gordon,
Yes you can.
--chris
Posted by Chris Gerhard on September 04, 2009 at 04:30 PM BST #