Disk drive selection for user, reseller packages

Sakamoto Ryōma

Sakamoto Ryōma

Verified User
Joined
Jun 4, 2011
Messages
69
Hello

If a dedicated server has an SSD and HDD, it can be good if an admin can decide who can use which disk drive.

Because of SSD limitation in size (because of its cost) it can be used for overall system performance (and may be some important websites (users or resellers)). And HDD space can be assigned to some resellers where they may not waste the premium SSD space.
 
So I guess you have two mount-points:

/home on HDD
/home2 on SSD

so you need to have a choice where to create a new user?
 
SSD or 15K SAS

The basic reasoning is performance drives are expensive and premium, and personally I dont want to share it with every users in my dedicated server.

@scsi
I wrote SSD for performance but someone may prefer 15K rpm drives. I dont think using SSD drives which are SLC controller is an extremely bad idea.
 
Best uses for SSD drives would be for swap, or logging, or if big enough, partitioned to use for both. If I had a choice I'd make sure to have enough memory to not need to rely on swap, and use SSD drive for logging.

Why logging? Because everything used for logging requires moving drive heads if it's sharing space on a physical drive with anything else. And that takes time.

Why for swap? Because when you're using swap you end up with a lot of services waiting, and server load goes up rapidly.

Putting home for a user on an SSD drive won't save that much time if there's a swap problem, not much either than as compared to logging.

Because logging and swap are both serverwide issues which will still effect a user on the SSD drive.

Jeff
 
no ssd discussion

Actually I asked for a feature request which you can define storage mediums for a reseller or a user. And the thread name is "Disk drive selection for user, reseller packages", but it turned out to be a discussion whether it is good idea to use SSDs on server or not. There are lots of discussions on web hosting forums about SSD usage on servers, and if dont mind you can discuss that on that forums.

Example setup_

- SSD or 15k rpm HDD as a main operating system disk
- home on main OS disk
- home2 on 7200 rpm HDD

@Jeff

If I have a swap problem I would think to add more RAM rather than adding an SSD.
 
I apologize for my part in keeping the thread offtrack, and I'll refrain from doing that again. But I will respond to your question directly to me.

Note that I also said to have enough memory to not rely on swap, and to use the separate SSD (and I'll add now, any higher speed drive, separately) for logging, as slow speed logging can and often will slow down server response.

I know that sometimes the kernel uses swap even when you've got lots of spare memory. I don't know why (I suppose it would make a great discussion on one of the kernel mailing lists if it hasn't already been done).

For example:
Code: 
top - 10:25:10 up 120 days, 14:30,  1 user,  load average: 0.16, 0.40, 0.36
Tasks: 257 total,   2 running, 254 sleeping,   0 stopped,   1 zombie
Cpu(s):  5.0%us,  0.4%sy,  0.0%ni, 94.4%id,  0.1%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  12289688k total, 10287996k used,  2001692k free,   825832k buffers
Swap:  3148732k total,       12k used,  3148720k free,  7713120k cached
True only 12k in this instance but this is very underused server and shouldn't have any.

A problem I see is that if you change the home directory you're also changing it for email, and could require complex changes in how DirectAdmin handles email (I haven't checked, but it seems reasonable).

Hopefully your original question will be responded to by DirectAdmin staff soon.

Jeff
 
Hello,

At this time, if you'd like to have a partition choice for User creation, it would need to be done with the user_create_post.sh.
Create the User to /home, then use the script to change the /etc/passwd with usermod, rewrite configs, and any other places it's set.

Right now, the /etc/exim.conf has /home/ hardcoded for performance reasons, so can't be a default DA option, but can be changed to do a lookup for the correct home path for the User (it gets very long and messy though)
Beyond that /etc/virtual/domain.com/passwd stores home paths, but it's based on the true home path, so just make sure you set the home partition for that User before creating any email account.
Be sure to run:
Code: 
echo "action=rewrite&value=httpd&user=[b]username[/b]" >> /usr/local/directadmin/data/task.queue
The custom package items could be used for this.
Couple examples:
http://help.directadmin.com/item.php?id=299
http://help.directadmin.com/item.php?id=260

John
 
Dovecot uses the paths in /etc/virtual/domain.com/passwd. DA creates those paths based on /etc/passwd, so as long as the new home is set before any emails are created, it should be fine.
 
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