Am 19.02.2013 20:59, schrieb Gordan Bobic:
On 19/02/2013 19:42, Reindl Harald wrote:
>
>
> Am 19.02.2013 20:24, schrieb Gordan Bobic:
>> On 19/02/2013 19:05, Reindl Harald wrote:
>>>
>>>
>>> Am 19.02.2013 20:02, schrieb Gordan Bobic:
>>>>> what exactly do you need to align on the partitions?
>>>>
>>>> For a start, making sure your RAID implementation puts the metadata
>>>> at the end of the disk, rather than the beginning.
>>>
>>> "my RAID implementation"?
>>> LINUX SOFTWARE RAID
>>>
>>> and this is how the raid-partitions are looking
>>> no problem since years
>>>
>>> Disk /dev/sda: 2000.4 GB, 2000398934016 bytes, 3907029168 sectors
>>> Units = sectors of 1 * 512 = 512 bytes
>>> Sector size (logical/physical): 512 bytes / 512 bytes
>>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>>> Disk identifier: 0x0000ae2c
>>> Device Boot Start End Blocks Id System
>>> /dev/sda1 * 2048 1026047 512000 fd Linux raid
autodetect
>>> /dev/sda2 1026048 31746047 15360000 fd Linux raid
autodetect
>>> /dev/sda3 31746048 3906971647 1937612800 fd Linux raid
autodetect
>>>
>>> [root@srv-rhsoft:/downloads]$ sfdisk -d /dev/sda
>>> # partition table of /dev/sda
>>> unit: sectors
>>> /dev/sda1 : start= 2048, size= 1024000, Id=fd, bootable
>>> /dev/sda2 : start= 1026048, size= 30720000, Id=fd
>>> /dev/sda3 : start= 31746048, size=3875225600, Id=fd
>>> /dev/sda4 : start= 0, size= 0, Id= 0
>>
>> That's the MD partition alignment, not the alignment of the FS space within
the MD device. The two are not the
>> same.
>
> maybe you should read older posts in the thread
Looking for what, exactly?
> [root@srv-rhsoft:/downloads]$ tune2fs -l /dev/md1
[...]
This won't tell you the FS alignment against the raw underlying disk sectors.
> Blocks per group: 32768
This is sub-optimal in almost all cases except RAID1 or single-disk, as I explained
earlier
how do you meassure "sub-optimal"?
the time wasted to re-install a complex setup and start configuration
from scratch, especially if you have more than one clones of the same
machine will never be worth 1,2.3% of theoretical performance
so i do not give a damn about a few percent and as long SSD's are
way to expensive to store some TB in RAID setups they are no
option and if they are at a valid price they are free from
early-adopters problems
as said: NOW i would not save any important data on a SSD
and i do not own any unimportant data beause if it is
unimportant i go ahead and delete it at all
maybe you install from scratch regulary
i do never and i am on board since Fedora Core 3