General procedure for installing to an SSD?

[tashirosgt]

The Guides&Solutions section of the forum has a useful guide to using solid state drives in Fedora (http://forums.fedoraforum.org/showthread.php?t=277082) once you have a running system installed. I'm trying the visualize the most efficient method for installing Fedora on a system with an SSD from scratch. What is the order of operations?

Perhaps people can offer some criticisms of how I think about this (since I haven't tried it yet).

I assume installing from the live CD is still a good way. I assume its not good to select the default partitioning scheme. I don't know whether using LVM is a good idea. Some of the configurations mentioned in the guide involve setting options in the /etc/ fstab file. I assume you can't do that until you do the installation and have an /etc/fstab file.

One technique mentioned in the guide is to put the /var/log filesystem on a conventional hard drive, if the system has one. Should I do this in the custom partitioning phase of installation from the live CD? (I've never used that interface, so I don't know what can be done with it. I assume it lets me run fdisk.)

I'm curious what other directories could be advantageously mounted on a spinning disk. (I plan to have a laptop drive as my spinning disk.)

The general way I visualize the installation from the live CD is that you would do a custom partitioning. You would then do the "copy Fedora to hard drive" phase in the normal way. Then you would do further customization before installing addtiional packages or updating.

[diamond_ramsey]

Cool!!! I hope to find out, too. There is an SSD in my future!!!

[StefanJ]

I'll hop onto this thread since I'm having some trouble with such an install.

The SSD part wasn't the problem.

I started with a system which had all partitions on a single hard drive.

I physically added two 500 gb SATA drives and a Crucial 64 gb SSD.

I used Disk Utility to partition the SSD (/boot and / partitions), to create a RAID out of the two 500 gb drives, and then to partition the RAID into /home, swap, /tmp, and /var (for logs).

I put a FC16 86_64 Live install on a thumb drive. Booted from it.

When partitioning choices were presented, I selected the custom options.

The utility that the installer used could "see" the SSD, and it showed the RAID as well, but the RAID entry was grayed out. I couldn't edit it or use the existing partitions.

Knowing I wasn't doing anything permanent, I let the install continue and got an "everything on the SSD" install, which seemed to go fine. But it is not what I want, so I reenabled the original drive for another go once I learned more.

Since the RAID is empty, I could break it apart and try the install again, hoping it would then give me the opportunity to reassemble the RAID and recreate the /tmp, /var, /home and swap partitions.

(If all goes well, I would copy the contents of /home from the old drive onto the RAID . . . and then move the old drive into an enclosure to use as a backup.)

[stevea]

Originally Posted by tashirosgt

The Guides&Solutions section of the forum has a useful guide to using solid state drives in Fedora (http://forums.fedoraforum.org/showthread.php?t=277082) once you have a running system installed. I'm trying the visualize the most efficient method for installing Fedora on a system with an SSD from scratch. What is the order of operations?

A/ Go ahead and partition & install, aligning the partitions.
B/ After booting the new system, edit the /etc/fstab adding 'discard' options (or more) on all the mountable partitions (swap takes care of itself).
C/ reboot and verify the mount options [look at the output of "mount" or "mount | grep discard".
D/ Run the 'fstrim' command on the mounted file systems.
E/ everything else. The elevator=noop is a microscopic improvement. 'noatime' really cuts down on accesses but it can wait till day2 moving the /var /tmp to other partitions isn't so awful that you can't configure it after the first week.

The most critical issues are a/ partition alignment, b/ getting 'discard' mount option running and c/ 'fstrim' -ing any cruft left after the install. The other items are optional and can wait.

Perhaps people can offer some criticisms of how I think about this (since I haven't tried it yet).

I assume installing from the live CD is still a good way. I assume its not good to select the default partitioning scheme. I don't know whether using LVM is a good idea. Some of the configurations mentioned in the guide involve setting options in the /etc/ fstab file. I assume you can't do that until you do the installation and have an /etc/fstab file.

Personally I boot a live CD and use gparted to create the partitions properly aligned. Then I use gparted to create the file systems and swap with labels. Then later during a DVD install I just spec the paritions to use for /, /home and swap. At this point in history I would also run gdisk to create a mirror GUID and a 2MB BIOS partition.

You can do similar from the 'disk druid' in the DVD installer. The live CD install is more limited in options, but so long as the partitions are aligned on big-boundaries you are fine.

Whether you use LVM or not is not dependent on the SSD drive. My *opinion* is that few end-users ever need LVMs features, and it imposes limitations and a small performance penalty. I don't use it, even on my soho server. In the near future we will be using btrfs and dropping LVM I think. Btrfs has similar functional features as LVM built in, plus more.

One technique mentioned in the guide is to put the /var/log filesystem on a conventional hard drive, if the system has one. Should I do this in the custom partitioning phase of installation from the live CD? (I've never used that interface, so I don't know what can be done with it. I assume it lets me run fdisk.)

It's very easy to do this after the install - so I'd wait until you have all the other stuff working.
Make a partition, add it to /etc/fstab with /var/log as the mountpoint, reboot.
tmp

I'm curious what other directories could be advantageously mounted on a spinning disk. (I plan to have a laptop drive as my spinning disk.)

The rule is - if you write the directories A LOT (wear) or if you don't care if the content access is relatively slow - then move it to a spinning disk. For example your music & vid collection don't require superb speed. You might try putting all of /var on a rotating disk - those yum caches and logs under /var are huge and only used occasionally.

The general way I visualize the installation from the live CD is that you would do a custom partitioning. You would then do the "copy Fedora to hard drive" phase in the normal way. Then you would do further customization before installing addtiional packages or updating.

Yes, thats good, it's the way I would do it, but it's not that critical. It seems marginally better to get the 'discard' mount option working and the fstrim accomplished before starting any serious work.

Just for example when you "yum install" a package it loads an rpm file and installs the contents and creates a bunch of working tmp files and then it deletes the tmp files and rpm. If you have 'discard' working then the deleted file blocks become re-usable by the SSD. If you don't have discard working, then the blocks can't be reused until your disk gets filled, crufty & slow or until you run 'fstrim'.

So long as the disk has extra 'virgin' space - then installing all the packages etc, then later fixing 'discard' then running fstrim is OK.

---------- Post added at 08:30 PM ---------- Previous post was at 08:26 PM ----------

sudo fstrim /
sudo fstrim /home
sudo fstrim /other/mount/point

[marko]

One technique mentioned in the guide is to put the /var/log filesystem on a conventional hard drive, if the system has one.

Since /var/log is tiny compared to /var/cache, doesn't it make more sense to go for broke and put the entire /var on spinning disk?

My current /var/log is only 26MB but /var/cache is 190 MB and when updates occur I'm sure the total writing and deleting throughput into /var/cache/yum is way more than anything going on in /var/log. Probably one update cycle of a hundred + packages is equal to months of writing the log files to /var/log

[stevea]

/var/log has a lot of writes (ssd wear) - so it's a prime candidate for removal.
/var/cache and /var/tmp and aren't written too often, but they contain a lot of rarely accessed yum/rpm stuff.

There are a few structures down /var/run that you might want on SSD, but they'll probably be in buffers anyway.

So yes all of /var is a candidate to put on rotating storage.

[marko]

Another issue, isn't it possible this SSD wear issue is obsolete (we're attributing the bad lifespan that the old first gen SSDs had to the current ones)? I just got a Samsung 830 128GB SSD. If I install Fedora 16 I'll probably use 20 or 30GB and have 100 GB of space left. Even if I leave the /var/log on the SSD, with 100 GB free and good wear leveling, there'd be plenty of time before blocks start wearing out IF the controller evenly works over the free blocks. Basically I'd probably upgrade to some other disk before it wears out.

They say an average block can be written hundreds of times, I'd have to write 100s of TB to wear out that 100GB of free space.

http://www.voicesatsamsungsemiconduc...all-important/

[tashirosgt]

A slight digression. I'll state these obvious facts about SSDs because they weren't obvious to me until I actually ordered some!

There are (at least) two different physical types of SSDs and a seemingly definite model name (like Intel SSD 320 Series) doesn't necessarily tell you which type the drive is.

The "2.5 inch SATA" type have the same SATA connectors as conventional non-laptop and laptop spinning SATA drives. They fit in mouting hardware that holds "2.5 inch" laptop drives. They take the same SATA style power connector and voltage as the non-laptop and laptop spinning SATA drives.

The "1.8 inch micro-SATA" type are smaller physical size, they require a different voltage and they have different data and power connectors than non-laptop and laptop spinning SATA drives. If you want to use this type of drive in a computer that is designed for the "2.5 SATA" spec drives, you can get an enclosure that adapts the micro-SATA SSD to be like an SSD. (See the Youtube http://www.youtube.com/watch?v=gi9CEzr7BD8). If you intend to use the micro-SATA in a desktop case, you will need both this type of enclosure and also the mounting hardware to set the enclosure in a 3.5 inch or 5 inch bay.