[AusNOG] Server/HD Question

Chris Ricks chris.ricks at securepay.com.au
Thu Feb 14 17:41:30 EST 2013 

I'm not sure where this idea of having to hunt down the exact same model
of RAID comes from. This isn't the case.

The vast majority of vendors maintain upward compatibility for their
metadata formats. Further, if a RAID controller failure results in
having to "hunt" for a new controller that is compatible then you should
probably assess the worth of the applications hosted - warranty support
is there for a reason.

If recovery of data is the goal post controller failure, this can be
done quite easily with losetup+mount .

Regards,

Chris

On 14/02/13 14:55, Jake Anderson wrote:
> On 14/02/13 14:43, Skeeve Stevens wrote:
>> OK, so today is a day of learning.
>>
>> As I said.. I am NOT a server hardware guy.  Based on some of the
>> responses, I now have learned that SATA drives will fit into a SAS
>> interface (but not the reverse).  This is awesome... I thought they
>> were completely different.
>>
>> So, it is a DELL 1950 with 32Gb ram, 2 x Dual Core 3Ghz processors.
>>  I am still unclear what, if any RAID is on board.
> I would stay away from "hardware" raid, if you don't need it for
> ultimate performance use software raid.
> When the computer craps itself, slap the drives into a new host and be
> running again, no need to hunt down the exact same model of raid card.
>
>>
>> The server will be used for a dozen VMs.  Centos, general purpose,
>> DNS, radius, etc with httpd front end and some mySQL backend, but all
>> low performance.  The sort of VMs you commit 128mb of ram to and max
>> at 1-1.5Gb ram.
> you can never have too much ram, this applies double with VM's ;->
>>
>> FYI, I know how to manage Vmware and staggering the boots, and so on.
>>
>> Oh yeah.. and I did mean 7.2k drives.. ;-)
>>
>> So.. now that I know I can use SATA drives... it opens things up a bit.
>>
>> I am looking at Ingram.. still some thing I don't understand.
>>
>> HP 2TB SATA 6Gb/s 7200 HDD
>> <https://au.ingrammicro.com/_layouts/CommerceServer/IM/ProductDetails.aspx?id=AU01@@2210@@10@@000000000001885395> -
>> $292
>> HP 2TB SATA 3Gb/s NCQ 7200 HDD
>> <https://au.ingrammicro.com/_layouts/CommerceServer/IM/ProductDetails.aspx?id=AU01@@2210@@10@@000000000001551449> -
>> $342
>>
>> No idea what NCQ is, and why the faster TP drive is cheaper.  Anyone?
> NCQ is native command queing, the HDD will re-order buffered reads on
> the fly for the best average access time.
> Can be a decent gain on a heavy disk load.
>
>>
>> These look nice:
>>
>> SEAGATE Constellation CS SATA 2TB 3.5" 7200RPM 64 Cache
>> <https://au.ingrammicro.com/_layouts/CommerceServer/IM/ProductDetails.aspx?id=AU01@@2210@@10@@000000000002145465> -
>> $159 lots in stock
>> SEAGATE Constellation CS SATA 3TB 3.5" 7200RPM 64 Cache
>> <https://au.ingrammicro.com/_layouts/CommerceServer/IM/ProductDetails.aspx?id=AU01@@2210@@10@@000000000002145467>  -
>> $219 lots in stock
>>
>> I see some NL drives (assuming what someone said was Near Line) - no
>> idea what that is though.
>>
>> I was also thinking that if the chassis had the space, I should put a
>> little SSD of CF on board to install the ESX onto to keep the OS off
>> the drives... thoughts?  My assumption is that once VMware is booted,
>> its disk access is minimal.
> I would doubly not do this, or if you do, raid them.
> SSD's have the same failure rate as rotating media. Often with worse
> failure properties, one day they just disappear, no degradation, bad
> sectors or anything first.
> I would put a RAID1 in for boot and put your OS on that.
> however you configure the rest of the array, its good if the system
> can still get booted regardless of the degradation.
> Given a number of VM's running partitioning is perhaps a good thing to
> look at, rather than one bigass raid5 array, put a few smaller raid1's in.
> Spread the VM's across the spindles so if a mail system starts
> thrashing grabbing somebodies emails, when their mail client starts
> pushing it back onto the file server you aren't running all that on
> the same set of spindles.
> Be sure to align all the VM's with sector boundary's. Right the way
> through the chain. IE the VM's internal partitions should start on a
> boundary of the physical disk.
>
>
>>
>>
>> ...Skeeve
>>
>> *Skeeve Stevens - *eintellego Networks Pty Ltd
>> skeeve at eintellegonetworks.com
>> <mailto:skeeve at eintellegonetworks.com> ; www.eintellegonetworks.com
>> <http://www.eintellegonetworks.com/>
>>
>> Phone: 1300 239 038; Cell +61 (0)414 753 383 ; skype://skeeve
>>
>> facebook.com/eintellegonetworks
>> <http://facebook.com/eintellegonetworks> ; linkedin.com/in/skeeve
>> <http://linkedin.com/in/skeeve> 
>>
>> twitter.com/networkceoau <http://twitter.com/networkceoau> ;
>> blog: www.network-ceo.net <http://www.network-ceo.net/>
>>
>> The Experts Who The Experts Call
>>
>> Juniper - Cisco - Cloud
>>
>>
>> On Thu, Feb 14, 2013 at 1:10 PM, Skeeve Stevens
>> <skeeve+ausnog at eintellegonetworks.com
>> <mailto:skeeve+ausnog at eintellegonetworks.com>> wrote:
>>
>>     Hey guys,
>>
>>     I know a bit about operating servers, but know bugger all about
>>     the hardware, especially when it comes to hard drives.
>>
>>     I am needing to deploy a server for some low performance VM's,
>>     and it has 32Gb ram, Dual core dual processor 3Ghz... so all
>>     good.  Should run a few linux VM's on ESX.
>>
>>     But... hard drives I really don't know about.
>>
>>     The chassis takes SAS drives.  In it are some small drives and I
>>     want to upgrade.
>>
>>     Will 7.5k speed drives be ok on a VMware server if its not for
>>     high performance processing?  The cost of 15k SAS drives still
>>     seem to be rather expensive.  I was hoping for 500Gb-600Gb of space.
>>
>>     Any thoughts on which brand is ok... I will be putting a single
>>     drive in mirrored (only 2 bays).
>>
>>     ...Skeeve
>>
>>     *Skeeve Stevens - *eintellego Networks Pty Ltd
>>     skeeve at eintellegonetworks.com
>>     <mailto:skeeve at eintellegonetworks.com> ; www.eintellegonetworks.com
>>     <http://www.eintellegonetworks.com/>
>>
>>     Phone: 1300 239 038; Cell +61 (0)414 753 383 ; skype://skeeve
>>
>>     facebook.com/eintellegonetworks
>>     <http://facebook.com/eintellegonetworks> ; linkedin.com/in/skeeve
>>     <http://linkedin.com/in/skeeve> 
>>
>>     twitter.com/networkceoau <http://twitter.com/networkceoau> ;
>>     blog: www.network-ceo.net <http://www.network-ceo.net/>
>>
>>     The Experts Who The Experts Call
>>
>>     Juniper - Cisco - Cloud
>>
>>
>>
>>
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