Yeah Red Hat, basically just says take the default. I was just curious if anyone had any other facts on the whole deal when using U2.
If you use lvm striping you can specify a chunk/stripe size. If you just use it without any of the mirroring/striping features, there is not chunk/stripe size. Its new hardware, and they are ssd's. There is no hardware RAID, so, the "specialists" are recommending LVM instead of RAID because it passes through discard/TRIM support. I hate new parts. On Mon, Nov 28, 2011 at 4:53 PM, George Gallen <[email protected]>wrote: > Didn't realize you set a chunk size on an LVM, thought that was a hardware > RAID only feature. > I would think the chunk size would be dependent on the number of drives in > the stripe and > The average size of a record in the database. > > When I setup our RAID array, I went with the default chunk size, but did > have the option to > Reduce it if I wanted to, but chose not to, since the speed was pretty > good (15K SAS drives) > > George > > -----Original Message----- > From: [email protected] [mailto: > [email protected]] On Behalf Of Wols Lists > Sent: Monday, November 28, 2011 4:37 PM > To: [email protected] > Subject: Re: [U2] Question about lvm stipe size - What block size does UV > write in? > > On 28/11/11 18:15, John Thompson wrote: > > So I'm setting up a lvm striping plus mirrorring configuration with 4 > disks > > to use for a Universe database in Linux. > > > > And I'm curious, what block size does UV write in? > > > > Is it 4k blocks? Less or more than that? > > By default, iirc, it's 4K. INFORMATION was 2K. But why should that > matter as far as your RAID is concerned? > > > > As far as lvm or raid, what stripe sizes are your RAID arrays or LVM > > volumes set to? 64k? > > And what size does your DISKS have their buffers set to? I think the > modern default is 4 *meg*. > > > > Our current machine is set to 64K, but, I was just curious if there is > some > > recommended size to use. > > I am referring to a stripe size in a RAID array or lvm logical volume. > > > Can't give you any advice, unfortunately, other than to say it's > complicated, and you probably need a specialist. If you're running > licenced RHEL, I'd get Red Hat to advise. My instinct would be to go for > whatever the disk buffers are, but I think that's the wrong choice... > > Cheers, > Wol > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users > _______________________________________________ > U2-Users mailing list > [email protected] > http://listserver.u2ug.org/mailman/listinfo/u2-users > -- John Thompson _______________________________________________ U2-Users mailing list [email protected] http://listserver.u2ug.org/mailman/listinfo/u2-users
