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I have about 3 OS's, including 2 flavors of 'untu, on each of two laptops. So far Ubuntu has been great at handle my predilection for extra partitions. This has been the case with 14.04, 14.10 and 15.04.So far.

I like lots of small partitions for backups - one around 700MB for CD backups, another another larger one for DVD's, one sized for my old 2GB flashdrives, maybe a 16 and a 32 for transfers with larger USB 3.0 flashdrives. It is easy to wipe unused disk space or entire partitions which is a great convenience and security enhancement.

I have never had trouble reading partitions with gpart, Partition Wizard and usually can mount partitions with occasional issues when permissions conflict. Some of my partitions are encrypted by one of my many Linux OS's and some are unencrypted.

My addiction to lots and lotsa partitions entered a new phase when I discovered that, as Rod Smith points out, Ubuntu spreads its boot and boot configuration files for Grub over two partitions. I had a problem getting my 'untu installs to show on the boot screen and discovered that it is easy to get grub to update via the recovery mode log in when I tried out installs with root, boot and home partitions rather than the more typical two-partition install.

Thus, with an average of three OS's per laptop, and an interest in going to a quad-boot, that would leave me with around 14 partitions counting the Windows Recovery partitions and my own boot partition backup.

I did have a problem with an Ubuntu-based distro(Mint) which, after some updates, could no longer read an encrypted drive. I had to reinstall and that issue leaves me wondering if, as i proceed with various updates, if Ubuntu might not be able to guarantee its performance with a very unusually complex network of partitions.

My question is whether I am courting disaster. Is there a signifgant risk that at some point my disc controller or some other system function will simply crash and burn when and if I add one too many small partitions? And, for that matter, is there some sort of major performance penalty I pay? So far so good, but I would heed the advice of those with different experience.

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    You do know that backups on same drive are useless when drive fails, and drives do fail. I also prefer to only have / with /home inside it, but then a large data partition that you mount in all installs. depending on distro ownership & permissions may be an issue, but share NTFS for sharing with Windows works everywhere.
    – oldfred
    Jan 31, 2016 at 20:04
  • Yes I noticed that in your excellent how-to tips and tricks but seems like I get really good luck with grub set up correctly from the git go using the / as well as /boot and /home method. And yes a big partition they all use. although actually all my Linux distros see the Windows partition 100%.
    – Flag Bear
    Feb 5, 2016 at 2:20

2 Answers 2

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No, your controller and other hardware do not care how many partitions you have, there is no reason for your specific concern.

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  • And so, this answer is assurance also that there is not some kind of cache or buffer in grub or Ubuntu or the firmware which would be overun with lots and lotsa different partitions? I ask because in part, reading on this forum, and others, that the instructions for installs often suggest that fewer partitions is preferable, an instruction which baffles me as almost some kind of unreasonable prejudice of a kind.
    – Flag Bear
    Jan 30, 2016 at 18:21
  • Number of partitions for installation of an OS is purely subjective and based on the need/want of the installer or customer. One partition or eight will not make a difference in dependability or reliability of the system or hardware.
    – acejavelin
    Jan 30, 2016 at 19:03
  • OK, thanks. Since I like having 3-4 OS's, each with 3 partitions, and intermediate , backup and recovery partitions, I didn't want to be coming backfor help if it was common knowledge that there was a limit to how far one could take this. I it seems as though the GUID setup allows for unlimited numbers of partitions. I still wonder why so many installation advice writers urge people to minimize the number of partitions, but as there does not appear to be a technical specification I suppose it is just a matter of keeping things simple to avoid human error.
    – Flag Bear
    Jan 30, 2016 at 21:10
  • With MSDOS style partitions, you are limited to 4 primary partitions or 3 primary and 1 extended with any number of logical partitions up to a total of 15 partitions (this is an OS limit imposed by Windows and Linux, not a partition table limit). A GUID partition table can contain up to 128 partitions. Again, the hardware doesn't care how many partitions you have, it will have no impact on it's life. But keep in mind "normal" wear things, like if you image DVD's to a 8GB partition hundreds of times per day on an SSD drive, you may encounter other issues in exceeding it's write life.
    – acejavelin
    Jan 30, 2016 at 21:16
  • But you should still use some common sense and logic. There is no need to have 100 partitions for 99.99% of applications, even with multiple OSs and HDDs. But if you have 4 OS's with 4-5 partitions each, and a few for specific purposes and large one for general data storage, I don't see any technical issue with this as long as you can keep it all straight. Having 30-40 partitions and constantly wiping them could spell disaster with one slip of a finger on the keyboard or mouse.
    – acejavelin
    Jan 30, 2016 at 21:19
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As has been stated in some comments, there is no hardware issue with the number of partitions; disk controllers and disks deal in sector numbers, and neither know nor care what data is on those sectors or to which partition the sector is allocated. AFAIK, OS-level disk caches are also not a concern.

The old Master Boot Record (MBR) partitioning system is limited to four primary partitions, one of which can be an extended partition that can hold an arbitrary number of logical partitions. Note that the MBR limit sometimes creates problems because a disk might already have four primaries, which makes creating additional partitions difficult. This isn't really the point of your question, though. The newer GUID Partition Table (GPT) defaults to a limit of 128 partitions; however, this limit can be raised if necessary (few tools enable such a change, but gdisk can do it).

The MBR and GPT limits are based in the data structures themselves. OSes and disk utilities may impose lower limits. IIRC, recent versions of Windows have no set limit, although the usual mapping of drives to letters in the Roman alphabet, starting with C:, means you can map no more than 24 filesystems in this way. (I think older versions of Windows had a lower limit -- probably 16 or 24 -- but I don't recall the details.) There was originally a limit of, IIRC, 16 partitions in the Linux kernel; however, modern distributions, including Ubuntu, provide ways around that limit, with the workarounds activated by default. I have created, as a test, both MBR and GPT disks with vastly more than 16 partitions -- around 100, IIRC. The Linux distributions I used for this (Gentoo and Ubuntu, IIRC) handled these disks just fine. I never tried these disks in Windows, so I don't know how it would react. Ditto for FreeBSD and other OSes. If you're booting in EFI mode, or even with a computer that uses EFI firmware, you should also consider how it would react, which is something I've never tested. It's conceivable that an EFI might flake out and hang if fed a disk with a hundred partitions. This reaction might vary from one EFI to another, too, so even if you hear of either a success or a failure, that result might not apply to your computer.

In sum, you should be safe with up to about 16 partitions under any circumstances. If you want to go beyond that limit, you may want to test using a USB flash drive or a spare hard disk, to be sure your firmware and all your OSes can handle it.

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  • Been up to 17 or 18 but maybe that is risky.
    – Flag Bear
    Feb 5, 2016 at 2:18

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