Hard Disk IDs in Linux

Dan Egli ddavidegli at gmail.com
Wed Mar 20 01:32:15 MDT 2013


*Kewl! I like it. Thanks for the URL. I'm keeping that in mind if I ever
need something that big. :)*

* *

*--- Dan*


On Sat, Mar 16, 2013 at 2:47 PM, S. Dale Morrey <sdalemorrey at gmail.com>wrote:

> Just curious but have you considered something like this...
> http://blog.backblaze.com/category/storage-pod/
>
> On Sat, Mar 16, 2013 at 4:04 AM, Dan Egli <ddavidegli at gmail.com> wrote:
> >> For a home server I recommend RAID1 or RAID10 over RAID6.
> >
> > Really? I guess between RAID6 and RAID10 it's not much different, but
> what
> > about someone who has say six or eight disks in the server? I'm curious
> why
> > you'd still recommend RAID10? Hypothetically speaking, let's assume I
> > wanted to have a server big enough to hold 1 year of downloaded data from
> > the net, downloading at approx 5Mbps (with TCP overhead, that comes to
> > approx 1 MB every 2 seconds) 24/7/365. That's nearly 16 TB. A RAID6 could
> > handle that with 6 drives, 4TB each. A raid10 would need 8 drives. I
> admit
> > each is possible to throw into a full tower case, but why spend the extra
> > money on two more drives, making the two raid10s? I am genuinely curious.
> >
> >
> >
> >
> >
> >> What kind of chassis? Most good chassis will do hardware RAID and
> >
> >> export the volumes. Though there are some bare disk arrays that simply
> >
> >> export devices as SCSI LUNs. Either way you need a chassis with a power
> >
> >> supply.
> >
> >
> >
> > Well, that's not really an issue because I finally realized I could break
> > my boss down by using some basic math. I showed him using basic
> > multiplication how long it would take to fill the 120TB array he wanted
> > (more than eight years to reach 25% capacity) and he FINALLY agreed that
> we
> > could do it much cheaper and easier by building a full tower PC and
> filling
> > it with Hard Disk Drives. So we're going to order the parts soon. Thank
> > goodness for that. I'm still not sure which chassis he wanted. I think he
> > was thinking of going to a company like Aberdeen or someone. I have
> > insufficent experience to state whether or not that was a good idea, but
> > thankfully it's a moot point now. I imagine we can fit about 10 disks in
> a
> > large case (I have to do some research on cases to find the one that will
> > let us hold as many hard disks as we can), and make a raid out of them.
> >
> >
> >
> >
> >
> >> I'm not sure how I feel about ZFS... ZFS is not a supported Linux file
> >
> >> system. It's third-party and licensing conflicts means you have to
> >
> >> compile the modules yourself everytime a kernel is updated. Though
> >
> >> this is largely automated these days with the dkms system that many
> >
> >> distros use. And maybe there are binary repositories.
> >
> >
> >
> >> I feel that ZFS in and of itself is stable and production-ready (I used
> >
> >> it for years on Solaris without issue). But I'm not sure of the status
> >
> >> of the zfs-on-linux project.
> >
> >
> >
> > So what would you use? Be aware that he's REALLY keen on using a file
> > system that includes journaling and data-deduplication. I don't know how
> > easy it's going to be to change his mind. It took near a week of
> arguments
> > before I got him to abandon the rackmount server idea. I'm well aware of
> > many of the advantages of file systems like Ext4 and JFS. But try
> > convincing my boss on that. He's one of those people who hears about some
> > new idea, likes it, and wants it implemented, despite not knowing how it
> > works internally or what would be involved in the implementation.
> >
> >
> >
> >> I get the impression your boss thinks the large disk array idea is on
> the
> > same
> >
> >> order of complexity as throwing disks in a box and setting up a software
> > RAID.
> >
> >
> >
> > EXACTLY. That's PRECISELY what he thought. He's all "Linux supports
> > software Raid! You've shown yourself that it can handle the number of
> > drives in the server that we'll have. So why not just throw the drives
> in,
> > connect them to the various controller cables, and build the raid?" and
> > didn't want to listen to ideas that it would likely be MUCH more
> > complicated than that. But now that he's finally agreed to a full tower I
> > just have to be sure we order either a motherboard with enough controller
> > ports on it, or order a separate controller card to handle whatever the
> > motherboard can't.
> >
> >
> >
> > What kind of an interface would you guys recommend? Now that he's
> resigned
> > to a PC tower case he's thinking standard SATA. While I'm sure that would
> > work, is there a better idea?
> >
> >
> > Thanks!
> >
> > /*
> > PLUG: http://plug.org, #utah on irc.freenode.net
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> > Don't fear the penguin.
> > */
>
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