[systemd-devel] bootchart issues on slow hardware

[Reindl Harald]

Am 18.03.2013 22:30, schrieb Holger Winkelmann:
> Just a quick note, Systemd is a core function on a core OS.
> and a coreOS is likely to be started from flash drives. We have
> i.e. ATCA devices starting from eUSB Sticks or even SD cards.

well, our ESXi starts also from a SD-card

/dev/md1       ext4   29G    6,4G   23G   23% /
/dev/md0       ext4  477M     30M  447M    7% /boot
/dev/md2       ext4  3,6T    1,6T  2,0T   44% /mnt/data

but you won't do this for such environments
with RAID10 and 3 RAID-devices over 4 disks

and yes such environments will be perfectly useable
and fast as long core-functions are not starting do
get developed in igorant way what hopefully won't happen

hint:
you will not reinstall such systems
you simply plug out all 4 disks and put them in
the new machine for many reasons

> ----- Original Message -----
>> ]] Reindl Harald
>>
>>> but keep in mind that for professional environments for many
>>> years SSD is no option for some TB of data and even if
>>> the price falls down you have to calculate redundancy for
>>> RAID10 environemnts which can not be raplced by a SSD
>>> due lack of relieability and no real-world expierience
>>> how long they run and how you detect errors before it is
>>> too late
>>
>> SSDs have been used in professional environments for quite some years
>> now.  Cost is still a problem, at least for large amounts of data.  Data
>> about reliability is certainly getting there and quite a bit of
>> knowledge is already present.  RAID10 is only one option, in many cases
>> you will get way better performance with RAID5 or RAID6 and SSDs than
>> spinning rust.
>>
>> Spinning rust still has its place, but not any place you need reasonable
>> I/O performance.
>>
>>> SD cards as example are way less relieable than any rotating
>>> media because for rotating media you get errors, a SD card
>>> happily confirms write-operations for hours and does not
>>> change the data on the meda, seen recently that after
>>> overwirte with /dev/zero and format with any known FS
>>> after pull out and plugin again the same data as two
>>> wekks ago was on the card without any single warning or
>>> error message besides a bricked phone by overheat
>>
>> SD cards compared to SSDs is about the same as floppy drives compared to
>> hard drives.  Not particularly relevant.
>>
>> --
>> Tollef Fog Heen
>> UNIX is user friendly, it's just picky about who its friends are
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>>
> 
> --
> 

-- 

Reindl Harald
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