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Anaconda's default partitioning scheme when installing to an SSD+HDD system (F21)

asked 2015-05-14 13:59:08 -0500

RunInCircles gravatar image

I've had the good fortune of getting a new workstation equipped with a 256GB SDD and a 1TB HDD. I've essentially split each drive in half to dual boot Windows 7 and Fedora 21. My intention is to use the SSD for the OS + frequently accessed files while using the HDD for bulk storage and any "write heavy" operations that might put unnecessary wear on the SSD. After installing Windows 7 to the two "half"-drives, I insalled Fedora using Anaconda's automatic "dual-boot" option to install along side a currently present OS.

Anaconda reacted by setting up LVM, with one volume group for all of the remaining free space on both drives. It then created three logical partitions within it: swap (17 GB), root (54 GB), and home (557 GB). The output of fdisk --list is shown below.

Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 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
Disklabel type: dos
Disk identifier: 0xac7c8796

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sda1  *         2048    206847    204800   100M  7 HPFS/NTFS/exFAT
/dev/sda2          206848 250161151 249954304 119.2G  7 HPFS/NTFS/exFAT
/dev/sda3       250161152 251185151   1024000   500M 83 Linux
/dev/sda4       251185152 500117503 248932352 118.7G  5 Extended
/dev/sda5       251187200 500117503 248930304 118.7G 8e Linux LVM

Disk /dev/sdb: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x55355c42

Device     Boot     Start        End   Sectors   Size Id Type
/dev/sdb1            2048  976762879 976760832 465.8G  7 HPFS/NTFS/exFAT
/dev/sdb2       976762880 1953523711 976760832 465.8G 8e Linux LVM

Disk /dev/mapper/fedora_dh3203--t1700--1-swap: 15.7 GiB, 16844324864 bytes, 32899072 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 /dev/mapper/fedora_dh3203--t1700--1-root: 50 GiB, 53687091200 bytes, 104857600 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 /dev/mapper/fedora_dh3203--t1700--1-home: 518.7 GiB, 556949045248 bytes, 1087791104 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/sdc: 14.9 GiB, 16008609792 bytes, 31266816 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
Disklabel type: dos
Disk identifier: 0x929e2b69

Device     Boot Start      End  Sectors  Size Id Type
/dev/sdc1        2048 31266815 31264768 14.9G  c W95 FAT32 (LBA)

Is this setup efficient as far as utilizing the disks? In other words, is LVM aware of how to best split up data between the SSD/HDD physical drives for good ... (more)

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Welcome to ask.fedora, and thank you for asking such a well thought out question and giving us so much needed information. I'm not familiar with SSD usage, so I can't answer that part of your question. I can tell you, however, that in my personal opinion, LVM is not a good solution for a personal computer, although it probably comes in handy on servers. If you're going to reinstall, you're probably better off using a custom partitioning scheme so that you can, among other things, have a separate /home that's not on the SSD.

sideburns gravatar imagesideburns ( 2015-05-14 15:50:51 -0500 )edit

Thanks for your suggestion! Interesting that Anaconda would default to using LVM for the "workstation" edition in that case, but it perhaps would be convenient if you wanted to transparently treat multiple drives as one big one. In regards to your suggestion, I wonder if it is possible to consolidate my logical volume (spanning one partition on each drive) to a single partition on only the SSD. That is, without reinstalling from scratch. Of course, using LVM wouldn't be necessary in this case, anyway.

RunInCircles gravatar imageRunInCircles ( 2015-05-14 16:04:22 -0500 )edit
1

I doubt that very many people have that need on workstations or home computers. I don't know why LVM is the default for workstations, but that goes back to before there was a distinction at install time between workstation and server. My guess is that the devs all use it and don't realize that it's not really needed for most private uses.

sideburns gravatar imagesideburns ( 2015-05-14 16:23:20 -0500 )edit

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answered 2015-05-14 18:54:22 -0500

baoboa gravatar image

updated 2015-05-15 04:11:30 -0500

you can use lvm caching to create hybrid lvm logical volume ( mixing slow and fast drive), this need command line actions and an understanding of lvm.

an automatic setup through anaconda would be nice ( dreaming )

here is some references

man page if lvmcache

nice blog from Richard WM Jones on the subject

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Thanks for the tip! I was actually able to apply this to my home partition after I did a reinstall. It's probably overkill in a certain sense, but the man pages on the lvm utilities are pretty helpful and it wasn't too hard to do.

RunInCircles gravatar imageRunInCircles ( 2015-05-18 13:37:52 -0500 )edit

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Asked: 2015-05-14 13:59:08 -0500

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Last updated: May 15 '15