[CentOS] Re: Anaconda doesn't support raid10

[Ross S. W. Walker]

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Ruslan Sivak
> Sent: Friday, May 11, 2007 3:32 PM
> To: CentOS mailing list
> Subject: Re: [CentOS] Re: Anaconda doesn't support raid10
> 
> Feizhou wrote:
> >
> >> Originally I had boot on 2 drives raid1, with 2 more drives being 
> >> hotspares.  Then I realized that this makes no sense, if 
> you can just 
> >> set up a raid1 with 4 drives (where each drive is a copy of each 
> >> other).  Didn't really know if it was supported, but looks like it 
> >> works.
> >
> > The entire use all four disks for /boot makes no sense if two disks 
> > belonging to the same mirror for the lvm go down. Please stop this 
> > nonsense about surviving everything to no benefit. You can 
> have three 
> > disks fail and still have a working /boot. For what?
> > _______________________________________________
> 
> Feizhou,
> 
> After thinking about it for a little bit, I see your point.  
> If one of 
> the arrays fails, the data drive is gone, and there is no 
> point keeping 
> boot after that.  This means it suffices to put /boot on the 
> first raid1 
> array. 
> However, as was mentioned elsewhere in this thread, by mirroring the 
> boot partition on all 4 drives, I don't have to worry about 
> which order 
> the drives are plugged in, and I can preserve disk symmetry.  
> Since the 
> cost of the drive is about $0.25 a GB, I think wasting the $0.10 is 
> worth the flexibility and peace of mind.

Don't worry about it, the 4 partition raid1 makes perfect sense in
your setup not for the reason you gave, but for:

1) simplicity
2) symmetry
3) flexibility
4) low to no overhead, 99.99% read partitions

It provides no downside and a lot of added bonuses.

So how is the performance on the striped LVM LVs?

Do you see the 120MB/s throughput?

Random I/O should also be as good as your drives allow.

-Ross

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