Tero Pesonen wrote:
I first looked at SCSI disks as a more reliable alternative -- if a disk can withstand server-level I/O for a few years, it sure as hell will stand up to anything I can throw at it on my humble desktop --
From a reliability pov, the really important difference is that SCSI drives are built for 24 hour daily operations, whereas PATA/SATA drives are typically built for 8 hours a day. Look up the MTBF numbers and you'll see that the manufacturers make certain assumptions about the duty-cycle.
In other words, may I combine disksfrom different manufacturers, with different specs, etc. without affecting the RAID somehow negatively?
Yes.
If one disk is slower than the others, will it impose the speed limit onto the RAID virtual block device?
I'm pretty certain it will, yes.
On the other hand, replacing disks later with larger capacity ones will cause no problem as they only need to meet the minimum size criterion. Hence, I could replace them one-by-one such that each new disk, replacing a removed old one, is first let to fully integrate/reconstruct; finally, after all disk have been replaced, I could enlarge a partition or two, for example, as allowed by the new shared minimum, thus increasing the capacity of the virtual device that is being RAIDed.
It might work, but if this is critical functionality, I'd test it first.
Also, I presume the kernel would not mind a non-RAIDed internal SATA disk(s) being part of the system as well.
Correct.
Would it be possible to have two separate RAID arrays? (as long as all the disk can be connected and there is space and power available...)
Yes.
Is it really true that the system may still boot gracefully after the disk where the MBR was dies and is replaced during a power down? How exactly will this work -- is the MBR too mirrored on all disks?
Yes.
To me this kind of setup seems now the most convenient one, especially with the guide available on how to install openSUSE with a software RAID and how to monitor it. I'd presume there would be no other benefits in going for SCSI over this except better performance?
Reliability and better concurrency/performance.
I also believe hardware RAID controllers would only improve performance, too, while possessing no other relevant factors affecting typical desktop use?
Correct.
One more question: Will I be able to access each disk's (that make the RAID) SMART data still with hdparm or even though the system would see them as a single block device? (Or so I presume, as they share the same mount points)
Yes.
I'd like to hear if the general ideas and arguments made above are more or less correct. I'm not going to order my new system just yet -- it is still a few weeks away at minimum, as is 11.1 too, I think -- but I'd like to think these issues through well beforehand.
I've only got 2 x 300Gb SATA drives in RAID1 in my workstation, but otherwise it sounds pretty much like what you're planning. /Per -- /Per Jessen, Zürich -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org