RHEL-5 64-bit OS Installation
 

Hi All,

I am going to install 64-bit RHEL-5 OS over a machine at my workplace soon, and having 2G RAM with 160GB HDD. I will use 6 CDs of the OS to install OS, and getting a bit confused with the partitions value. Also, is it better to involve RAID and LVM partitions from the very beginning ?

Could anybody please suggest me what would be the perfect partition values, provided we are going to install most of the users and softwares under /home and databases under /usr ??

Thank you all in advance,
Kapil.

No, sorry. No one can help you with this, since the "perfect partition values", depend on the server, what it's going to be doing, and what YOU, as the administrator, have determined best meets the needs.

If your really not sure what partitions to use, then there is also the option of using an LVM, not a fan of it myself, but it'll allow you to resize partitions within it.

With LVM, you pretty much have to have it from the beginning else partitions you already have can't be transferred into it and thus aren't resizable. Anything and everything you want to be resizable has to start within the LVM itself. Raid can be set-up later down the line via mdadm but is much easier to set-up during installation process itself. If I remember correctly Raid does not like to appear in an LVM but an LVM will happily appear within a Raid. It could be the opposite way around... it's very rarely I have to set-up both on the same machine.

I would point out that a raid won't protect against any problems that LVM itself can potentially cause during resizing of a partition or infact anything a user does, Raid only protects against file system corruption loss and the protection offered depends on the Raid type used (note that raid 0 offers no protection, it in fact can be a larger risk then no raid but offers performance increases instead).

The only real advantage to LVM is that you can span one file across multiple drives, virtually everything else you can do with a regular setup. You can expand/contract(normal, non lvm) partitions with tools liked parted with relative ease. You can add drives in later by simply putting the mount point wherever you like, for all intents and purposes it is just another sub directory. Functionally I have no issue with LVM, until it blows. Once it blows (and as with all file systems it is when, not if) it is another layer that you have to deal with. Every layer one adds to a system reduces the chances of a good recovery outcome. You can also run into issues when trying to recover one lvm from a system that has its own lvm. You cannot have two LVMs on the same system with the same name, and most distros use the default name for the lvm.

I would agree with that, personally I am against resize of partitions all together, but I have never seen a guide on how to set partitions up right first time round... it's hard thing to get and needs experience. Personally the only time I have really resized a partition was using boot camp on my Mac Mini to dual boot vista~. And even that messed up and required me to have to use a facility to repair the partitioning...

Do I understand correctly you mean a single hard drive of 160GB (not multiple smaller drives totaling 160GB)?

Software RAID within a single drive is possible, but I can't imagine how it might ever be a good idea.

My own opinion of LVM matches what Lazlow wrote in post #4 of this thread.

The easiest and most flexible way to partition the disk is to just have a / partition and a swap partition.

As soon as you split anything (such as /home or /usr) out of / you are making a prediction about how much space will be needed by each side of that split. Any error in that prediction is a cost of the split. The split may also cost extra head motion while the system is in use.

So there needs to be a big benefit to splitting, to justify the costs. If you don't know what that benefit is for you, then you probably won't split right to get it anyway.

I will admit this is "do what I say, not what I do" because I split my own 500GB drive sloppily into many partitions. That made sense for me because:
1) 500GB was a lot more than I actually need so I don't care about using it efficiently.
2) I use Mepis and the upgrade from Mepis 7 to Mepis 8, as expected, went much smoother because I had extra partitions to play with.
3) The system is more experimental than production. Extra partitions give flexibility for playing with other distributions, etc.

I don't expect RHEL in 160GB at a workplace with "users" (I paid attention to that word being plural) would share any of those characteristics with my single user home Mepis system.

So unless you have a good understanding of why and how much you should split / don't split it.

If you have a good understanding of what you will be running on that RHEL system, you might be able to make a good estimate of how much swap space you will need. I doubt you have the necessary information to make any decent estimate of swap space needed. So make the swap partition 4GB and hope it was a good guess.