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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Mon Sep 30, 2013 5:26 pm Post subject: Gentoo on Asus UX51VZ/U500VZ with RAID0 |
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Hi!
Im looking to buy the Asus UX51vz with WQHD+ monitor and 2 SSD's in RAID0 (intel matrix, imsm).
Have tried searching around, but everything seems outdated and can't really find anything specific for this laptop.
Anyway, Arch Linux has a guide on how to install arch on this, but I want to use gentoo (with custom kernel, preferably without an initramfs)
Here's a link to the guide arch has: https://wiki.archlinux.org/index.php/ASUS_Zenbook_UX51Vz
So, is it that straight forward on gentoo too?
Any specific stuff I have to compile into the kernel? I already have a kernel config for the Asus Zenbook UX31 which works fine on the laptop I currently own, but this laptop doesn't have the raid0 configuration. Anything I have do edit ? |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Mon Sep 30, 2013 7:37 pm Post subject: |
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The perfect for me would be to have /boot and swap outside of the raid, and everything else (root, home) on raid0. (To my understanding it's not possible to have boot and swap in a raid setup)
Could someone please guide me through the disk setup in gentoo with this? Also, do i need an initrd/initramfs for this?
It should be noted that the raid is already setup on the computer with Windows 8, but I intent to remove the whole shabang and reinstall with gentoo only, but I need some assistance with this :) |
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ponky n00b
Joined: 26 Sep 2013 Posts: 8
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Posted: Wed Oct 02, 2013 11:34 am Post subject: |
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You have to use initrams in order to have / in raid. Just genkernel --mdadm --install initramfs, add initrd line to grub.conf + domdadm to kernel parameters and you're good to go. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Wed Oct 02, 2013 6:34 pm Post subject: |
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Really? Even if my /boot is outside of the raid?
And how would I go around setting up the raid in the first place?
The laptop comes shipped with a raid configuration, but I want to delete windows, and have it all in a raid0 configuration with gentoo. |
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ponky n00b
Joined: 26 Sep 2013 Posts: 8
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Posted: Thu Oct 03, 2013 6:27 am Post subject: |
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sPHERE911 wrote: | Really? Even if my /boot is outside of the raid?
And how would I go around setting up the raid in the first place?
The laptop comes shipped with a raid configuration, but I want to delete windows, and have it all in a raid0 configuration with gentoo. |
Well, I guess you could use kernel autodetect but it's deprecated afaik. Initramfs is the right way to go. Also kernel autodetect only works for raids with metadata 0.90.
What's so horrible about initramfs?
I'd suggest you to disable raid from laptops bios and creating a 100% software raid. Those fake raids are bad 99% of the time. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Thu Oct 03, 2013 6:41 pm Post subject: |
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I think its already setup with a software raid, so i guess i can just delete it and create a new.
Whats the fastest raid0 setup with linux?
There are so many options, i dont even know what options to use.
I prefer to not have a initramfs because of bootup speed. |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54237 Location: 56N 3W
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Posted: Thu Oct 03, 2013 7:30 pm Post subject: |
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sPHERE911,
Linux in kernel raid and your BIOS 'fakeraid' are both software raid. In raid0, performace wise there is little to choose between them.
However, raid0 gives you zero redundency ... so its just 'aid' :) data is written to each drive in the raid set in turn to increase the data transfer speeds.
There s little for the CPU to do.
/boot must be outside the raid, or set up in raid1. If you want to use grub1, /boot, if its raided, must be metadata version 0.90
root ( / ) can be raided without an initramfs only if you use metadata version 0.90 and kernel raid auto assembly.
raid metadata version 0.90 and kernel raid auto assembly are both depreciated. Its no longer the mdadm default either.
why do you think that an initramfs will slow down your boot?
It may if you use genkernel but if your roll your own lean, mean initramfs, it won't do anything you don't need.
The [url=wiki.gentoo.org]Gentoo Wiki[/url] will tell how to set up raid. It probably describes raid1. Raid0 is the same apart from the parameters you feed to mdadm -C _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Thu Oct 03, 2013 8:03 pm Post subject: |
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Thank you for your excellent answer.
however, what is the drawbacks of metadata 0.90? |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54237 Location: 56N 3W
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Posted: Thu Oct 03, 2013 8:36 pm Post subject: |
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sPHERE911,
Unless you plan on using more than 26 disks - none at all.
There is the risk that kernel raid autoassembly may be removed from the kernel at some point. This happens to depreciated features from time time.
Were that to happen, you would need to add an initramfs to assemble your raid before you could update to such a kernel. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Fri Oct 04, 2013 2:43 pm Post subject: |
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NeddySeagoon wrote: | sPHERE911,
Unless you plan on using more than 26 disks - none at all.
There is the risk that kernel raid autoassembly may be removed from the kernel at some point. This happens to depreciated features from time time.
Were that to happen, you would need to add an initramfs to assemble your raid before you could update to such a kernel. |
I understand! Well, part of the the point of gentoo for me, is to be "futureproof" , so I guess Im going to need an initramfs ;)
will this do?
Code: | genkernel --install --no-ramdisk-modules --mdadm initramfs |
Also, Arch has this wiki for the same laptop. https://wiki.archlinux.org/index.php/ASUS_Zenbook_UX51Vz
How much of that is applicable for gentoo?
I see that they use some kind of intel matrix metadata when assembling the array? |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54237 Location: 56N 3W
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Posted: Fri Oct 04, 2013 7:55 pm Post subject: |
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sPHERE911,
I've never used genkernel, I roll my own initramfs. The Wiki gives the method.
You will need to mdadm to the initramfs in that example. Thats well documented elsewhere, including a few of my posts on these forums. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Mon Oct 07, 2013 5:09 pm Post subject: |
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NeddySeagoon wrote: | sPHERE911,
I've never used genkernel, I roll my own initramfs. The Wiki gives the method.
You will need to mdadm to the initramfs in that example. Thats well documented elsewhere, including a few of my posts on these forums. |
I've been reading something about Btrfs having built-in raid features? I cant seem to find a detailed guide for that setup with gentoo. Can i skip the whole mdadm and initramfs by setting it up through btrfs? |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54237 Location: 56N 3W
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Posted: Mon Oct 07, 2013 5:37 pm Post subject: |
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sPHERE911,
There are several problems with btrfs.
First, its not yet in the kernel, so root on btrfs requires a specially patched kernel. btrfs is not stable yet. It may eat all your data at any time without warning, then go on to drink all the beer in your fridge. As long as you know what you are getting into, you can use btrfs.
btrfs does not need mdadm to set up the raid but mdadm works with any filesystems.
I use LVM on (mdadm) raid _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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sPHERE911 n00b
Joined: 23 Mar 2008 Posts: 50
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Posted: Mon Oct 07, 2013 6:16 pm Post subject: |
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NeddySeagoon wrote: | sPHERE911,
There are several problems with btrfs.
First, its not yet in the kernel, so root on btrfs requires a specially patched kernel. btrfs is not stable yet. It may eat all your data at any time without warning, then go on to drink all the beer in your fridge. As long as you know what you are getting into, you can use btrfs.
btrfs does not need mdadm to set up the raid but mdadm works with any filesystems.
I use LVM on (mdadm) raid |
Okay thanks, I assumed it was in the default kernel as it was in the default kernel of Arch Linux. Anyway, do I need a initramfs if I use the raid setup through btrfs and build btrfs into the kernel?
Thanks for all your help so far! |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54237 Location: 56N 3W
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Posted: Mon Oct 07, 2013 6:34 pm Post subject: |
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sPHERE911,
No, as the raid will be free with btrfs. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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