[Novalug] best hard disk setup for home file server?

Tue Oct 13 16:20:19 EDT 2009

Heh :)

I'm speaking mostly in terms of sofware raiding though, where you won't 
have issues with confusing your raid controller by mixing models. If you 
go with a hardware solution, I'd probably keep the drive models 
consistent.

-Ed.

Thus spake Richard Ertel:

> uh-oh. debate time. GO!
>
> On Tue, Oct 13, 2009 at 16:02, Ed T. Toton III <bones at necrobones.net> wrote:
>>
>> I don't see a direct harm in mixing drive models, aside from slight
>> variations in performance and capacity (the latter can be dealt with by
>> using the smallest common size). Arguably there's an advantage here as well,
>> since buying multiple disks from the same manufacturing batch has sometimes
>> led to rapidly successive failures as they wear out in unison.
>>
>> -Ed.
>>
>>
>>
>> Thus spake Richard Ertel:
>>
>>> you continue to make good points, which continue to ruin my good (in
>>> foresight, not hindsight) plans
>>>
>>> i already have four 3.5" 500 GB drives in my backup server, so i
>>> thought to myself "i can buy four 2.5" 500 GB drives and make an 8
>>> drive RAID-5 array.
>>>
>>> but they would of course be different models... crap.
>>>
>>> new possible plan: buy two 3.5" 1TB drives to match two i already
>>> have, make a 3 TB RAID-5 array. also buy four 2.5" 500 GB drives and
>>> make a 1.5 TB RAID-5 array. and deal with having 2 different volumes.
>>>
>>> i think i'm going insane
>>>
>>> On Tue, Oct 13, 2009 at 15:37, Bryan J. Smith <b.j.smith at ieee.org> wrote:
>>>>
>>>> From: Richard Ertel <richard.ertel at gmail.com>
>>>>
>>>>> i prefer one volume group because that's the most efficient way to
>>>>> store a bunch of files.
>>>>
>>>> Not when you mix disks of different models in my book.  It's asking for
>>>> various
>>>> issues.  I only use one volume group per model of disks.
>>>>
>>>> Heck, I use different volumes for different types of storage.
>>>>
>>>>> if i have 2 TB of movies, for example, but two 1.5 TB volumes, then i
>>>>> have
>>>>> to split the group somehow. seems messy to me.
>>>>
>>>> Okay, let me step back.
>>>>
>>>> I usually have a RAID-1 (or 10) volume for filesystems I'm going to write
>>>> heavily to as RAID-5/6 is going to be much slower.
>>>>
>>>> I then have a RAID-5 or 6 (or 50 or 60) volume for filesystems I'm going
>>>> to
>>>> do very little writing to, largely reading from, as it will act like
>>>> RAID-0 minus
>>>> one (or two in the case of RAID-6) disks, from a performance standpoint.
>>>>
>>>> So the former is my root, /tmp, /var and anything else that has lots of
>>>> writes.
>>>> The latter is my /usr, /usr/local, /opt, and data filesystems.
>>>>
>>>> I _never_ create one big filesystem or even one big data filesystem for
>>>> that
>>>> matter.  E.g., on my home server, I have the following volumes ...
>>>> - /export/(servername)/users -> /home/(subdomain)/users
>>>> - /export/(servername)/static -> /home/(subdomain)/static
>>>> - etc...
>>>>
>>>> The "static" share is for read-only media, like music, movies, etc...
>>>> And even
>>>> then I have ".old" filesystems for archiving older information, which I
>>>> eventually
>>>> move off-line.
>>>>
>>>> Segmenting data is always ideal for filesystems.
>>>> And segmenting volume groups is always ideal for types.
>>>>
>>>> So while I understand why you'd maybe have all data in one volume group,
>>>> I dont' know why you'd mix'n match disks to do it.  Seems like a recipe
>>>> for
>>>> many issues.
>>>>
>>>> My current server has (remember, I have 12 x 2.5" bays):
>>>> - (4) RAID-10 250GB = 500GB usable RAID-10
>>>> - (7) RAID-5 250GB = 1.5GB usable RAID-5
>>>> - (1) spare 250GB
>>>>
>>>> My server will have it's RAID-5 switched to:
>>>> - (4) RAID-5 500GB = 1.5GB usable RAID-5
>>>>
>>>> [ NOTE:  This does not include the two 2 x 2.5" trayless bays I use for
>>>> backups.  I currently have 4 x 320GB drives as my backup disks.  It
>>>> also does not include the fact that I'm sync'ing important data back to
>>>> Florida, or my LTO drive (still in Florida, I haven't moved it). ]
>>>>
>>>> I'm planning on recycling one more 500GB drive as a spare from one
>>>> more system in the next month or two.
>>>>
>>>> If I really need "a few more hundred GBs" for data, I can "borrow"
>>>> then from the RAID-10 VG and mount that filesystem where needed,
>>>> until I increase my storage at a latter date (like when 500GB drives
>>>> drop under $50, or I recycle my 640GB or latter drives, etc...).
>>>>
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>>
>> ------------------------------------------------------------------
>> - Ed T. Toton III, RHCE --|-- www.necrobones.com -- ed.toton.org -
>> ------------------------------------------------------------------
>> The ultimate result of shielding men from the effects of folly is
>> to fill the world with fools.
>>                -- Herbert Spencer, English Philosopher (1820-1903)
>>
>

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- Ed T. Toton III, RHCE --|-- www.necrobones.com -- ed.toton.org -
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