how many primary partitions i can have on each disk?

[skos]

I know i can have only 4 primary on one hard disk, but if i have more disks say 3 can i have 4 primary in each one?

[passerby]

Yes.

[Orbmiser]

As stated yes. But curious some reason you need more primaries?
Just wondering if there is some specific need for primary only? As always open to learning something new.
As I have 6 partitions on 1 disk and Linux runs on 3 extended partitions.
And triple boot 3 Os'es on it.

[srs5694]

Also, the limit of four primary partitions applies to disks that use the Master Boot Record (MBR) partitioning system. If you use the newer GUID Partition Table (GPT) system, the disk can support up to 128 partitions by default, and that limit can be raised with the right software. (GPT doesn't distinguish between primary, extended, and logical partitions; all partitions are similar to MBR primary partitions.) GPT is most often used on newer computers that use the EFI or UEFI firmware -- especially those that shipped with Windows 8, although many Windows 7 boxes and "bare motherboards" shipped in the last couple of years also support EFI, as do a few from earlier years.

[bigj231]

To add on something here, you can use GPT with BIOS as well. At least you can on newer boards.
See this thread on the Arch forums for additional info: https://bbs.archlinux.org/viewtopic.php?id=147238

[DrHu]

I think Primary partitions are good for completely separating OS(s) from each other, if you use extended/logical partitions you tie your alternate OS into the health of the OS that created the extended partitions..

So, I would prefer to use this setup
2 hard drives

• Windows OS on first drive
  --primary partitions or mix of Primary and extended
• Linux OS(s)
  --same as above
• Grub2x or windows bootloader (NTLDR) on first drive, controlling boot across all drives/partitions..

Also I tend to think that even with the option of having 128 slices available(partitions), I would prefer to have fewer, even with fairly larger hard drives: for example 4TB or increasing in the future ?
--too much data or data names (hard drive areas: slices/partitions) is too much information overload for me at least.
http://www.high-rely.com/hr_66/spotligh ... orld-12tb/

[skos]

Sorry for the delay. WORK

I know i must have 3 primary and 1 extented with as many logical i want, on one hard disk.

The reason i ask for the number of primary partitions is that i suspect the i have a problem with one of my partitions.
The thing is that i already have total of 4 primary partitions on my hard disks and some extended.
I tried to mount a primary partition ext4 that for a reason i dont remeber never used and since then i cannot (the OS) automount all the other primary partitions.

[altair4]

You know what would help is if you post the output of the following command so that the folks here can see what you are talking about:

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sudo parted -l

And if you need asistance about one of your partitions posting the output of these commands will aid in that help:

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sudo blkid -c /dev/null

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cat /etc/fstab

[srs5694]

I think Primary partitions are good for completely separating OS(s) from each other, if you use extended/logical partitions you tie your alternate OS into the health of the OS that created the extended partitions..

That's not really true, although there is a hint of something true that's remotely similar: Logical partitions are defined in a linked-list data structure, which means that the definition of the first logical partition includes a pointer to the next one, which in turn includes a pointer to the third, and so on to the end of the list. Thus, if an early logical partition's data structure is damaged, that will disrupt access to subsequent logical partitions in the list. Such damage is pretty rare, but it does occur from time to time. Note that this is damage to the partitions, not to the OSs, filesystems, or data contained within those partitions. So if you have (say) Ubuntu on /dev/sda5 (the first logical partition) and Mint on /dev/sda7 (the third logical partition), and if your Ubuntu installation is damaged without actually damaging the logical partition data structure, you'll still have no problem using Mint. Most damaged OS installations do not involve damage to partition data structures.

Also I tend to think that even with the option of having 128 slices available(partitions), I would prefer to have fewer, even with fairly larger hard drives: for example 4TB or increasing in the future ?
--too much data or data names (hard drive areas: slices/partitions) is too much information overload

Just because you can create up to 128 partitions doesn't mean you have to. Here's the partition table on one of my GPT disks:

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$ sudo gdisk -l /dev/sdb
GPT fdisk (gdisk) version 0.8.5

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 625142448 sectors, 298.1 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): B58D5E92-7BFB-4488-94B9-2F1BCFDD86DB
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 625142414
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048          514047   250.0 MiB   EF00  Unused ESP
   2          514048          923647   200.0 MiB   8300  /boot
   3          923648       625142414   297.7 GiB   8E00  Linux LVM

Note the line that specifies that the partition table holds up to 128 entries -- it's a normal-sized GPT. Yet only three partitions are defined, and gdisk displays information on just those three partitions. If I were to use parted or GParted, the results would be similar -- they'd show just the three defined partitions and nothing more. It's kind of like having a 4TB disk with 200MB of data on it -- most of the disk is available for use should you need it, but there's no compulsion to use it. There's no extra cost to having space for 128 partitions, though, unlike a big hard disk, for which you presumably paid more money than you'd have paid for a smaller one.

The reason i ask for the number of primary partitions is that i suspect the i have a problem with one of my partitions.
The thing is that i already have total of 4 primary partitions on my hard disks and some extended.
I tried to mount a primary partition ext4 that for a reason i dont remeber never used and since then i cannot (the OS) automount all the other primary partitions.

What sort of a problem? It's usually better to fix a problem rather than just throw more resources (e.g., more hard disks) at the computer in an effort to bypass the problem. In the latter case, the problem will still exist, and some types of problems will create bigger problems if left unattended. For instance, if you're having problems with bad sectors on the hard disk, that could be a sign that the disk is failing, and such problems can grow to affect additional partitions. In this case, replacing the hard disk is in order. That's just one example, though, and I'm not suggesting it applies to you -- I don't have sufficient evidence to know. Posting the information that altair4 requested, along with a description of whatever symptoms you're seeing, will help us give you better advice.

[DrHu]

I know, I know, people use RAID and all sorts of disk arrangements.
--I won't argue about the data structure/or coding of disk partition or access requirements: it probably doesn't help that much in a practical sense to know/understand that a logical partition is part of a linked-list

• I do actually like LISP
  --the linked-list programming language; I find it quite elegant..

I only think for a standard desktop user, this (a complex partitioning scheme:schema) unnecessarily complicates any archiving/backup and restore facilties

• --although, of course, with the correct planning and procedures in place it can be managed: but maybe not so easily; even experts unless they keep using the same data tend to have to read some preamble information in order to know what to do next.

As to altair4's post: OK
--but YES in the first post's (passerby) answer is correct, and that was really the only question the original poster proferred.

• 4 primary partitions per hard drive: part of dos/intel history..