Re: [gentoo-user] Xen with Gentoo as dom0: sw or hw raid?

[R0b0t1]

I would strongly suggest softraid. And qemu.

Re: [gentoo-user] Xen with Gentoo as dom0: sw or hw raid?

[J. Roeleveld]

On July 20, 2016 6:13:36 PM GMT+02:00, Jarry  wrote:
>Hi Gentoo-users,
>
>I'm going to build a small server with Xen-hypervisor with
>Gentoo as dom0 (if it is possible). Comming from ESXi-world,
>there is no choice (only true hw-raid is supported).
>
>But what about Linux? What's preffered way to go? Software-raid
>(mdadm), or true hardware raid-controller? I have a few spares
>(LSI-9271), these worked quite well with ESXi but I'm not sure
>they are supported by Linux at all, and if there is actually
>some way of monitoring controller-health...
>
>Concerning sw-raid, I have used it for quite some time, but
>never with Xen (is it actually possible?). Moreover, grub-config
>for Xen itself is somehow more complicated and sw-raid could add
>extra complexity...
>
>So the question is simple. For Xen-server with Gentoo as dom0,
>what do you recommend: sofware- or hardware-raid?
>
>Any other general tips concerning Xen (particularly with Gentoo
>as dom0)?
>
>Jarry

Short answer: if Linux kernel supports it. It will work inside the dom0.

Whatever is best depends in your requirements as linux sw raid can perform 
better that hw raid.
But. For Xen ensure you dedicate at least 1 core exclusively to dom0. Don't 
have any of your guests (domU) access the same CPU core as your dom0 uses.

As for grub complexity. I don't find this difficult. And even using UEFI boot 
for Xen isn't too difficult.
This is based on using either grub1 or EFI. Not using grub2 on any of my Xen 
machines.

--
Joost
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: [gentoo-user] nfsv4 issues

[Tom H]

On Sun, Jul 24, 2016 at 3:37 AM, Adam Carter  wrote:


> I've added the directory, and after restarting syslog now has new entries;
>>
>> kernel: [912267.948883] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4
>> state recovery directory
>> kernel: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery
>> directory
>>
>> I will test shortly and report back - thanks!
>
> Confirmed - this fixes the 30 second delay.

Good.


> Should i log a bug for these issues?

If I were you, I'd definitely file a bug reports against nfs-utils for:

1) the creation of "/var/lib/nfs/v4recovery/" when systemd is pid 1;

2) the systemd unit compatible envvars.

Re: [gentoo-user] nfsv4 issues

[Tom H]

On Fri, Jul 22, 2016 at 8:22 PM, Adam Carter  wrote:


 Does "/var/lib/nfs/v4recovery/" exist?
>>>
>>> No
>>> # ls /var/lib/nfs/
>>> etab export-lock rmtab rpc_pipefs sm sm.bak state xtab
>>
>> IIRC, it's needed to avoid this delay. I thought that I'd saved a url
>> about this but I can't find it.
>>
>> Do you have a syslog message about "stable storage"? "man nfsdcltrack".
>
> There's no message about stable storage, but there's this;
> kernel: [578030.628415] NFSD: the nfsdcld client tracking upcall will be
> removed in 3.10. Please transition to using nfsdcltrack.

It's from

https://patchwork.kernel.org/patch/1730241/


> # which nfsdcltrack
> which: no nfsdcltrack in
> (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/5.4.0:/usr/lib64/subversion/bin:/opt/vmware/bin)
> # qlist nfs | grep nfsdcltrack
> #

It depends on the nfs-utils USE settings:

# qlist -U nfs-utils
net-fs/nfs-utils (libmount nfsdcld nfsidmap nfsv4 nfsv41)

# qfile $(which nfsdcltrack)
net-fs/nfs-utils (/sbin/nfsdcltrack)


>> The openrc script has
>>
>> 
>> mkdir_nfsdirs() {
>> local d
>> for d in v4recovery v4root ; do
>> d="/var/lib/nfs/${d}"
>> [ ! -d "${d}" ] && mkdir -p "${d}"
>> done
>> }
>> 
>>
>> but systemd doesn't have anything equivalent. On RHEL and Ubuntu,
>> "/var/lib/nfs/v4recovery/" is created at installation time. Perhaps
>> the Gentoo ebuild should do the same or should ship a
>> "/usr/lib/tmpfiles.d/var-lib-nfs.conf" to create it at boot if it
>> doesn't exist.
>
> I've added the directory, and after restarting syslog now has new entries;
> kernel: [912267.948883] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4
> state recovery directory
> kernel: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery
> directory
>
> I will test shortly and report back - thanks!

Good luck. You're welcome.

Re: [gentoo-user] Re: MBR & GPT dual compliant format

[Neil Bothwick]

On 23 July 2016 04:29:50 CEST, James  wrote:
> R0b0t1  gmail.com> writes:
> 
> > On Jul 22, 2016 5:43 PM, "Neil Bothwick"  digimed.co.uk>
> wrote:
> > > I take it this is a limitation of Apple's firmware as I have set
> up a
> > > number of uUEFI systems and never had to do this.
> 
> > It is.
> 
> 
> There is another document that talks in depth about the issue,
> although
> it was centric to using gpt disk on a bios world that was slowly
> moving
> to efi [1].
> 
> 
> [1] http://mjg59.dreamwidth.org/8035.html
> 
> Here is the essence::
> "But most BIOSes (and most older operating systems) don't understand
> GPT, so
> plugging in a GPT-partitioned disk would result in the system
> believing that
> the drive was uninitialised. This is avoided by specifying a
> protective MBR.
> This is a valid MBR partition table with a single partition covering
> the
> entire disk (or the first 2.2TB of the disk if it's larger than that)
> and
> the partition type set to 0xee ("GPT Protective"). GPT-unaware BIOSes
> and
> operating systems will see a partition they don't understand and
> simply
> ignore it."
> 
> 
> I do not know how to set up a 'protective MBR', that's my issue. This
> reference goes on to talk about how the code was written for parted
> but
> never made the permanent status. It sure would fix a lot of
> installation
> issues among many different distros. An excellent read, if anyone has
> the
> time. Me, I'm going to use this method::
> 
> 1. First, write an example of what the partition table should look
> like.
> 
> 2. Figure out the separate tools & sequences to achieve the final
> result.
> 
> 3. Document the steps so they are clearly available for our community.
> 
> 4. Hope that one of the devs/hackers spins a patched version of a
> "parted"
> formatting tool to achieve this ability, system-rescue seems  to be
> the best
> home. Or if a patched parted only lives in an overlay, that would ease
> quite
> a lot of pain for many folks as in my research experience, setting up
> the
> disk partitioning schemes is the toughest part of an installation
> these
> days. This duality of disk usage  is critical to my cluster testing
> schema.
> I'll  also have a variety of bootstap codes to deal with from various
> embedded systems, in addition to commonly purchased hardware
> platforms, so
> extending the formatting to other forms of storage, in a consistent
> and
> generic way, provides an even greater appeal.
> 
> From the same doc::
> "It violates the spec and it confuses the majority of partitioning
> tools. I
> wrote some code to make parted do it at one point, but I don't believe
> it
> was ever merged. It's very difficult to make it work well. "
> 
> They discuss also some of the MAC family of issues and explain why
> macs
> still suffer from this malaise. I hope that code is still around
> 
> 
> Thanks for all the advice and help.
> James

Step 1: Use gdisk to create a 1M partition at the start of the disk. 
Step 2: Set its type to EF02
Step 3: There is no step 3,don't overcomplicate things, all the information you 
need has already been posted. 

-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.

Re: [gentoo-user] nfsv4 issues

[Adam Carter]

I've added the directory, and after restarting syslog now has new entries;

> kernel: [912267.948883] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4
> state recovery directory
> kernel: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery
> directory
>
> I will test shortly and report back - thanks!
>

Confirmed - this fixes the 30 second delay. Should i log a bug for these
issues?