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i try to speed up boot time of my linux server box which uses removable HDD rack's the current boot time is around 2 min's but if i connect the hdd's directly to the mainboard its about 2 sec's the problem is that ahci's kernel implementation causes a timeout of around 30 seconds for each disk during boot which originates from the hdd-rack after the timeout the kernel prints that the disk is limited with speed to 1.5gbps and udma/133 is used

so the question i have is: how can i set this in grub as a boot option so the kernel doesnt have to wait for a timeout and just hardcoded limits the speed of the disks? i read about a few options like pci=nomsi or such, which dont work

thats why im asking for limiting precisely the disks during boot

thx

James
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John Doe
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  • this question is fine for here, but may get better responses on Server Fault. please don't crosspost it there; it will be migrated automatically if necessary. if it is migrated, you need to register on Server Fault and associate your accounts to regain ownership of the post. – quack quixote Mar 07 '10 at 18:55
  • Is the ACHI timeout a BIOS or Linux kernel issue? – mctylr Mar 09 '10 at 02:03

1 Answers1

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Add this 

libata.force=1.5

to your boot options and it will force libata to 1.5Gbit. You can also force DMA modes etc, check out kernel-parameters.txt in your kernel documentation directory (or online say here)

James
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