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Old 03-26-2010, 01:14 PM   #1
rjo98
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Make disk druid take GB instead of MB


Ok, I've tried to reload a server 3 times, every time I try to setup 4 and 6GB partitions through the disk druid gui during RHEL install by entering 4096 and 6144MB, i end up with partitions showing 3.9GB and 5.9GB when i do a df -h after it boots.

Is there a way to make disk druid ask for GB instead of MB during the install process so i can just type 4 and 6 and it will show up right in a df -h.
 
Old 03-26-2010, 01:22 PM   #2
tredegar
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The filesystem free space is not going to be the same size as the partition size.

The filesystem itself takes up some space, how much depends on which filesystem (ext2-4, reiser etc.) and what parameters you have chosen to format it with. If you want 4GB of free space available, your partition is going to have to be larger than this.
 
Old 03-26-2010, 01:25 PM   #3
rjo98
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they're all ext3 file systems. below is a df -h. you can see the ones with .9's in them, i wanted them to be the next high whole GB. I was doing # of GB i wanted divided by 1024 to get the MB number for disk druid. guess that doesn't work.

Filesystem Size Used Avail Use% Mounted on
/dev/sda2 3.0G 235M 2.6G 9% /
/dev/sda9 108G 188M 102G 1% /opt
/dev/sdb1 1.1T 199M 1.1T 1% /data1
/dev/sda7 3.9G 73M 3.7G 2% /home
/dev/sda6 3.9G 73M 3.7G 2% /tmp
/dev/sda5 5.9G 1.4G 4.2G 25% /usr
/dev/sda3 5.9G 175M 5.4G 4% /var
/dev/sda1 190M 12M 169M 7% /boot
tmpfs 4.0G 0 4.0G 0% /dev/shm
 
Old 03-26-2010, 02:25 PM   #4
tredegar
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When you are posting listings like that, please use LQ's CODE tags - it makes it much more readable:

Code:
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5              42G   28G   12G  71% /
varrun                506M  192K  505M   1% /var/run
varlock               506M     0  506M   0% /var/lock
udev                  506M   80K  505M   1% /dev
devshm                506M     0  506M   0% /dev/shm
lrm                   506M   20M  486M   4% /lib/modules/2.6.24-27-generic/volatile
/dev/sdb1             367G  283G   66G  82% /media/disk
As I said, if you want 4GB of free space on your filesystem, then you'll need to create a partition larger than 4GB, because the filesystem itself takes up some space on the partition for inodes, journals and whatnot.

Also do not forget that for ext3 the default is for root to be allocated 5% of the free space for root's exclusive use, so this space cannot ever be used by normal users, who will find "No space on disk" when the disk reaches 95% full. There are very good reasons for this, but, if you wish, and understand the implications, this figure can be changed when the filesystem is created.

Try creating a partition of 4.4GB and formatting that as ext3. Then, even with root's 5% overhead, and the filesystem space, you should have 4GB free.

If it turns out to be 4.00001GB, who cares? But if you want exactly 4GB reported as "available", you may have to experiment for a long time with partition sizes and formatting options.
 
Old 03-26-2010, 02:43 PM   #5
rjo98
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Thanks, didn't know that the code tag would keep it formatted properly.

I guess I'm not concerned with the available space as much as i am with total space. I looked on some other server's anaconda.ks file and they use 4096, but maybe those drives are ext2 instead of ext3 or something?

I'm surprised there's no "magic number" to make volumes a certain size for Linux's various file system types.

Last edited by rjo98; 03-26-2010 at 02:54 PM. Reason: I can't type
 
Old 03-26-2010, 02:55 PM   #6
tredegar
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Quote:
I'm surprised there's no "magic number" to make volumes a certain size for Linux.
We don't care:
- Here's a disk.
- Partition and format it.
- If there's enough space, then use it.
- If you are about to run out of space, delete some stuff or add more space.

So, the actual numbers really do not matter, "enough space?" does. In general "more" is "better".
 
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Old 03-26-2010, 03:04 PM   #7
rjo98
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Unhappy

Quote:
Originally Posted by tredegar View Post
We don't care:
- Here's a disk.
- Partition and format it.
- If there's enough space, then use it.
- If you are about to run out of space, delete some stuff or add more space.

So, the actual numbers really do not matter, "enough space?" does. In general "more" is "better".
Geez, I'm almost sorry I asked this question now. I'm sure this question is beneath your skill set, but it appears I've upset you with my lack of knowledge, or you took offence to something I said, based on your response. Maybe someone else will read this post and reply constructively.

True, while i probably have "enough space" with 3.9 and 5.9GB partitions, that's not what i was trying to do, which is why i asked this question. I'm not one to settle for "good enough", i'd rather do what I set out to do, even if its a painful process.

Thanks for all the help so far though tredegar, hopefully someone else can chime in where you left off before this last post of yours.
 
Old 03-26-2010, 04:01 PM   #8
tredegar
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You misunderstand me, or perhaps I have not explained myself properly, or perhaps I do not understand the importance of 4.0GB free.
No offence intended.

The point I am making is that if you really want 4.0GB free, it's going to be very difficult, and probably not worth wasting time on.

One reason: The amount of space the FS needs for its own use in the partition you allocate to it depends on how you format it. It's all very well saying "ext3", but that has many extra options eg the "block size" [Bigger blocks = fewer inodes = less partition space used by the FS, but wastes partition space when you have many small files. It's a complete nightmare when you look at it closely].

Accepting the risk of criticism, please see man mke2fs and you'll see there are many options to creating an ext3 FS. Some of the options will use more "partition space" to store things needed by the FS. Others, less. It's a balance [time, money, space, speed], and usually, the best thing to do is accept the defaults.

Whilst it might be a "nice idea" to request exactly 4.0GB of "free space", nobody can be bothered to write the tools to achieve this (pointless) degree of precision, although I am sure it could be achieved. If you really wish to do this, I'll try to point you in the right direction.

Come to think of it, I don't think win handles this any differently: Format a 4GB partition as FAT32. How much "free space" do you have? Now format it as NTFS, how much "free space" do you have now?

Perhaps if you told us why you think you need exactly 4.0GB or 6.0GB, we'd be able to help further.

Cheer up
 
Old 03-26-2010, 04:09 PM   #9
rjo98
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Now when you're saying 4GB of "free space" are you talking how much is available to use currently, or the total size of the partition? I'm talking about total space on the partition (used space + free space) that i want to equal 4GB and 6GB.

I know what you mean about formatting FAT32 vs NTFS. But i'm looking more at partition total sizes.

The reason i'm trying to hit 4 and 6GB on the nose for the total size, not available size, is because when i look at the other servers i'm trying to load this one like (which i didn't load originally), they all say 4.0 and 6.0 on the nose, not 3.9 and 5.9 in the "size" column like mine does.

Hope that makes sense. no hard feelings here, i never thought making partitions a certain total size would be this hard in linux haha.
 
Old 03-26-2010, 06:26 PM   #10
tredegar
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Quote:
Now when you're saying 4GB of "free space" are you talking how much is available to use currently, or the total size of the partition?
I have already explained why the partition size (in GB) will be more than the filesystem "free space" (in GB). Please carefully re-read the above posts. I am trying to help you learn to solve your problem.

The filesystem you choose uses part of the partition space for storing, and indexing the filesystem. Exactly how much space on the partition the filesystem needs to use to accomplish this depends on how you format the partition.

Did you make the time to read man mk2fs, to understand this better ?

Quote:
I know what you mean about formatting FAT32 vs NTFS.
You might "know", but I doubt you have experimented, and tried this. If you had actually tried this test [formatting the same partition in different ways and looking at the "free space"], your understanding of filesystems (not just the linux ones) might be better.

Remember:
1] If you allocate more space to a partition, or filesystem, than is needed, nothing bad will happen.

2] If you allocate less space to a partition, or filesystem, than is needed, you might eventually, run out of space. [But this is probably easily fixable].

Quote:
The reason i'm trying to hit 4 and 6GB on the nose for the total size, not available size, is because when i look at the other servers i'm trying to load this one like (which i didn't load originally), they all say 4.0 and 6.0 on the nose, not 3.9 and 5.9 in the "size" column like mine does.
You don't need to "hit 4 and 6GB on the nose", anything equal or greater will do. As I said before, the exact number does not matter, but "more is better".

If this doesn't solve your question, then please post a very detailed explanation of exactly what you are trying to accomplish.

Last edited by tredegar; 03-26-2010 at 06:29 PM.
 
Old 03-26-2010, 08:32 PM   #11
jamescondron
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Christ, they'll give anyone a Linux job nowadays.

You want the installer to ask you for disk sizes in GB instead of MB, right? Perhaps you ought to consider why the installer is asking in MB as opposed to GB. If you can't answer it then dip into what the CD is doing and change it in source.

Or consider learning how many bits in a byte, how many bytes in a kilobyte, etc., etc.

If all you want is for your df outputs to look prettier, you may be in the wrong profession.
 
Old 03-27-2010, 01:40 AM   #12
rjo98
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Quote:
Originally Posted by tredegar View Post
I have already explained why the partition size (in GB) will be more than the filesystem "free space" (in GB). Please carefully re-read the above posts. I am trying to help you learn to solve your problem.

The filesystem you choose uses part of the partition space for storing, and indexing the filesystem. Exactly how much space on the partition the filesystem needs to use to accomplish this depends on how you format the partition.

Did you make the time to read man mk2fs, to understand this better ?



You might "know", but I doubt you have experimented, and tried this. If you had actually tried this test [formatting the same partition in different ways and looking at the "free space"], your understanding of filesystems (not just the linux ones) might be better.

Remember:
1] If you allocate more space to a partition, or filesystem, than is needed, nothing bad will happen.

2] If you allocate less space to a partition, or filesystem, than is needed, you might eventually, run out of space. [But this is probably easily fixable].



You don't need to "hit 4 and 6GB on the nose", anything equal or greater will do. As I said before, the exact number does not matter, but "more is better".

If this doesn't solve your question, then please post a very detailed explanation of exactly what you are trying to accomplish.
Geez, its like I'm getting ganged up on for being a newbie, way to have the posts go down the crapper with what seem to be rude comments yet again, just now from two people. I dont know if we're missing something in translation or what. I thought my posts were very clear from the get go, but let me try to answer some of the points in your last post tredegar.

tredegar, you said in your post "if you really want 4.0GB free". I'm trying to say that that is NOT what I want. Even in your first reply to me you're talking about 4GB free space. I never mentioned I wanted what's listed under the Avail column in my df to say 4GB, which would be 4GB free space. I want it to say 4.0GB under the Size column for /tmp and /home. Doing 3 times 1024 worked ok to make my / show up as 3GB which is ext3. it worked for my swap partition too, but that isnt ext3 so doesn't really come into play here.

Yes I read the man page for mke2fs, I realize i can change the reserved block percentage and resize inode. Me being a linux newbie, and posting in the linux newbie area, I don't really think doing this is up my alley yet, unless doing that outside of disk druid is required to make partitions, the way i read it that is just to fine tune the settings after partitioning them originally in disk druid during setup. Again, I'm new to this, so could be wrong, or partially wrong.

In another post you say "As I said, if you want 4GB of free space on your filesystem, then you'll need to create a partition larger than 4GB". Yes, I know that if i wanted a certain amount of free space on a partition, i would have to make that partition larger than that amount, but I never said that's what I'm trying to do. I wanted the partitions size, not its used space or free space, to be 4GB total. Unless all these times when you said "free space" you really meant "total partition size", which makes this very confusing. Is that what you meant?

This comment, not sure what you're basing that off of: "You might "know", but I doubt you have experimented, and tried this. If you had actually tried this test [formatting the same partition in different ways and looking at the "free space"], your understanding of filesystems (not just the linux ones) might be better." Considering I've been loading system with FAT32 and then NTFS for 15 years, I'm pretty sure when I say I know what you're talking about, I do. Actually I just did a demo of this in December for a group of 30 windows admins. Don't assume things just to be snotty.

You say "You don't need to "hit 4 and 6GB on the nose", anything equal or greater will do". well in my case I don't even have equal total partition size since i'm at 3.9 and 5.9, so based on your anecdote, this will NOT do.

"If this doesn't solve your question, then please post a very detailed explanation of exactly what you are trying to accomplish." I thought I was clear in my other posts, and I think you keep misunderstanding since in every post you keep saying I want 4GB and 6GB free space to show up in my df output, which isn't what i want. So lets try this: if you were loading a new RHEL server and needed to make ext3 partitions with a total size of 4GB and 6GB EXACTLY, what number would you enter for the MBs prompt on the disk druid screen during the creation of said partitions.

I'm not trying to get into a pissing match here. I hope you are just misunderstanding the original question like I'm thinking you are: you think i'm talking about free space when i'm actually talking about partition sizes.

Cant we all just get along?
 
Old 03-27-2010, 01:48 AM   #13
rjo98
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Quote:
Originally Posted by jamescondron View Post
Christ, they'll give anyone a Linux job nowadays.

You want the installer to ask you for disk sizes in GB instead of MB, right? Perhaps you ought to consider why the installer is asking in MB as opposed to GB. If you can't answer it then dip into what the CD is doing and change it in source.

Or consider learning how many bits in a byte, how many bytes in a kilobyte, etc., etc.

If all you want is for your df outputs to look prettier, you may be in the wrong profession.
Well, I already know there's 8 bits in a byte, 1024 bytes in a kilobyte, etc etc. All stuff I learned 16 years ago.

So James, how many MBs are in 4GB and 6GB? Since you allude to its so simple, I must be missing something, as when i entered 4096 and 6144 into disk druid and got 3.9 and 5.9GB partitions, yet when i entered 3072 i got a 3GB ext3 partition.

I don't want my df output to be "prettier", I want them to be what I intended them to be. I want them to be 4GB and 6GB partitions. I obviously didn't do something right, I'm not sure why i'm being crucified here for trying to get help figuring out what that is.

I mean, if you were trying to slice a drive up into partitions of certain sizes, wouldn't you want them to be the sizes you were actually trying to set them to, instead of being a little off?

Last edited by rjo98; 03-27-2010 at 01:53 AM.
 
Old 03-27-2010, 02:00 AM   #14
rjo98
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Quote:
Originally Posted by jamescondron View Post
Christ, they'll give anyone a Linux job nowadays.
Not sure what Christ has to do with Linux or my posts, but Linux support is a new part of my job, I'm just learning it now on the fly. I've been administering, setting up, planning multi-state deployments of windows workstations and server since 1995. I've also sold programs written in assembly language, C++, and VB. I'm not some tech inexperienced youngster trying to waste anyone's time here. James, I think you've even helped me with a couple other posts on here as your name looks very familiar, not sure what's with the comments this time around though.

Show me what I did wrong, or tell me where I misled you in what I posted, but please be constructive, not negative.
 
Old 03-27-2010, 02:44 AM   #15
win32sux
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Quote:
Originally Posted by jamescondron View Post
Christ, they'll give anyone a Linux job nowadays.
These type of personal remarks have a very negative impact on the atmosphere here at LQ please refrain from making such comments in the future. Let's stay focused on the question being asked, not the person asking it.
 
  


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