On 13 September 2017 at 12:00, hw hw@gc-24.de wrote:
It will depend on the type of SSD. Ones with large cache and various smarts (SAS Enterprise type) can take many different sizes. For SATA ones it depends on what the cache and write of the SSD is and very few of them seem to be the same. The SSD also has all kinds of logic which moves data around constantly on disk to wipe level so it makes it opaque. The people who have tested this usually have to burn through an SSD set to get an idea about a particular 'run' of a model but it doesn't go over every version of the model of SATA SSD.
Hm, so much to SSDs ... I can only hope they will be replaced with something better.
I have decided against putting anything onto these SSDs other than temporary data, but even for that, I would need to make an md-RAID, which I don´t want. It may work or not, and "may work" is not enough.
May work is part of any commodity hardware build. The SATA hard drives do not use the same technology as 4 years ago and you may end up with them having crap out on shorter lifetimes because they aren't built to live longer than 3 years depending on the model. [It doesn't matter the brand.. they get built with the same tech and at the same place these days.]
If the performance on the hardware RAID isn´t as good, it can not get worse than it is now, and it may be even better than with the SSDs.
I have two at home with the system installed on btrfs. I´m going to change that to md-RAID1 and xfs. Is there anything special involved in copying the system to another disk? Will 'cp -ax' do, or should I use rsync to copy xattrs etc.? Using the commonly used stripe size of 128kb is something I´d expect the SSDs being able to handle.
Depending on what CentOS you are working, cp -a will preserve xattrs.
CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos