CentOS - Nov 2017 - low end file server with h/w RAID - recommendations

John R Pierce wrote:
> On 11/2/2017 9:21 AM, hw wrote:
>> Richard Zimmerman wrote:
>>> hw wrote:
>>>> Next question: you want RAID, how much storage do you need?
Will 4 or 8 3.5" drives be enough (DO NOT GET crappy 2.5" drives -
they're *much* more expensive than the 3.5" drives, and >smaller
disk space. For the price of a 1TB 2.5", I can get at least a 4TB WD Red.
>>>
>>> I will second Marks comments here. Yes, 2.5" drive enterprise
drives have been an issue. +1 for the WD Red drives, so far 3.5" w/ 2tb and
4tb drives, ZERO issues. I've had good luck with HGST NAS drives too.
Unfortunately, that will come to an end soon (With WD owning HGST).
>>
>> Most servers can fit only 2.5" disks these days.  I keep wondering
what
>> everyone is doing about storage.
>
>
> 2.5" SAS drives spinning at 10k and 15k RPM are the performance
solution for online storage, like databases and so forth.   also make more sense
for large arrays of SSDs, as they don't even come in 3.5".    With
2.5" you can pack more disks per U (24-25 2.5" per 2U face, vs 12
3.5" max per 2U)... more disks == more IOPS.
That?s not for storage because it?s so expensive that you can only use it
for the limited amounts of data that actually benefit from, or require,
the advantage in performance.  For this application, it makes perfectly
sense.
> 3.5" SATA drives spinning at 5400 and 7200 rpm are the choice for
large capacity bulk 'nearline' storage which is typically sequentially
written once
Why would you write them only once?  Where are you storing your data when you
do that?

On 11/3/2017 1:31 AM, hw wrote:
>> 2.5" SAS drives spinning at 10k and 15k RPM are the performance 
>> solution for online storage, like databases and so forth.?? also make 
>> more sense for large arrays of SSDs, as they don't even come in 
>> 3.5".??? With 2.5" you can pack more disks per U (24-25
2.5" per 2U
>> face, vs 12 3.5" max per 2U)... more disks == more IOPS.
>
> That?s not for storage because it?s so expensive that you can only use it
> for the limited amounts of data that actually benefit from, or require,
> the advantage in performance.? For this application, it makes perfectly
> sense.
>
online high performance storage, vs nearline/archival storage. the first 
needs high IOPS and high concurrency.??? the 2nd needs high capacity, 
fast sequential speeds but little or no random access..??? two 
completely different requirements.? both are 'storage'.
>> 3.5" SATA drives spinning at 5400 and 7200 rpm are the choice for 
>> large capacity bulk 'nearline' storage which is typically 
>> sequentially written once
>
> Why would you write them only once?? Where are you storing your data 
> when you
> do that? 
I meant to say write occasionally.??? on a nearline bulk system, files 
tend to get written sequentially, and stored for a long time.


-- 
john r pierce, recycling bits in santa cruz

John R Pierce wrote:
> On 11/3/2017 1:31 AM, hw wrote:
>>> 2.5" SAS drives spinning at 10k and 15k RPM are the
performance solution for online storage, like databases and so forth.   also
make more sense for large arrays of SSDs, as they don't even come in
3.5".    With 2.5" you can pack more disks per U (24-25 2.5" per
2U face, vs 12 3.5" max per 2U)... more disks == more IOPS.
>>
>> That?s not for storage because it?s so expensive that you can only use
it
>> for the limited amounts of data that actually benefit from, or require,
>> the advantage in performance.  For this application, it makes perfectly
>> sense.
>>
>
> online high performance storage, vs nearline/archival storage. the first
needs high IOPS and high concurrency.    the 2nd needs high capacity, fast
sequential speeds but little or no random access..    two completely different
requirements.  both are 'storage'.
Not really.  You don?t put things into storage you?re using frequently or
all the time.  Instead, you keep them around where you can get at them
easily when you need them.  Usually, that isn?t a lot of things.

Storage is for things you don?t use as much and usually provides a lot of
room to put things.
>>> 3.5" SATA drives spinning at 5400 and 7200 rpm are the choice
for large capacity bulk 'nearline' storage which is typically
sequentially written once
>>
>> Why would you write them only once?  Where are you storing your data
when you
>> do that?
>
> I meant to say write occasionally.    on a nearline bulk system, files tend
to get written sequentially, and stored for a long time.
Data in a database is stored for a long time as well, and a lot of it isn?t
written to often, or basically only once.  A spreadsheet may be written to
more often, yet you might put it into storage because you have large amounts
of data like that.

For large amounts of data, 2.5" disks aren?t suitable.  Since there are
like
no servers at all you can buy used that fit 3.5" disks, I?m wondering what
everyone does about storage.  The servers that fit 3.5" disks were all sold
a
couple years ago, and even then it was difficult to find anything that would
have room for more than 6 disks.