Just some rambling thoughts, observations and niggling concerns regarding my current sme disk topology/setup.
I did an upgrade from sme 9.2 to sme 10 (yes, awhile ago now) from a 2 hdd raid1 setup to a 3 drive ssd main drive and hdd raid1 for /home/e-smith/files. The driving factor for the change in topology was the restore time for data in /home/e-smith/files on a 2 drive system. In my case it was taking the best per of a day. Granted it has only happened every few years but it was also an excuse to change things and have a play.
All good after the event.
Move forward a few years.
I was having a look at some smartdrive stats and noted that my primary ssd was down to 5% life time remaining. It doesn't have any reported failures or bad blocks/sectors and given that it is a 240gb drive with only about 13gb used on it I don't feel it is about to fail in the short term. Granted one of the points of making the change was to allow a quick and simple replacement of the operating system drive without the delay of the data restore. Also smallish ssd's are getting stupid cheap ~au$30/250gb drives.
Thoughts turned to what was the cause of the low life remaining on the ssd.
First obvious issue was I'd left some swap on it and even with 8gb ram it was utilising swap with a lot of free ram, so as a short term tweak I changed the swappiness of the kernel. I then had a look at the logging as another source of heavy writes with the thought of moving them to perhaps a ram disk aka folder2ram as used in openmediavault (debian based) but didn't find an equivalent for centos. I also looked at the size of /var/log and on my system it is ~4gb with journal of ~3.9gb which would need a lot of ram! I thought of just making a new partition on the raid1 hdd and mounting a volume there for /var/log and/or reducing the size of the journal. I researched reducing the size of a xfs formatted drive (I used xfs for the raid1 hdd partition) not looking good apart from a backup, repartition and restore to make the change.
So, after the long story.
I'm in no immediate rush and just pondering this. I have a suspicion that a few others on here have a similar layout so they might also have the same potential issue and/or a work around or some thoughts to add.
Simplest solution is to buy another small ssd, copy the existing ssd and swap them.
Change the size of the journal and work out how to use a ram drive for logging (with copies to/from disk on a reduced schedule to drop the number of writes down)
Rebuild the raid1 array to have partitions for /var/log and maybe swap as well as data.
Write about it on here and have a few beers (I don't like wine so that's out) and ponder.
Option 4 is winning and I can see option 1 being a required 2nd option if I spend to long on option 4.
4 Replies
1197 Views