vartec's questions

I have to run multiple instances of same app with slightly different settings. Only thing that changes is one command line parameter.

So currently I've got script which looks something like this:

[program:thing-one]
command=/usr/local/thing --instance one
user=a_user
stdout_logfile=/var/log/thing.log
autostart=true
autorestart=true
startsecs=10
redirect_stderr=true
directory=/
startretries=1000

[program:thing-two]
command=/usr/local/thing --instance two
user=a_user
stdout_logfile=/var/log/thing.log
autostart=true
autorestart=true
startsecs=10
redirect_stderr=true
directory=/
startretries=1000

[program:thing-three]
command=/usr/local/thing --instance three
user=a_user
stdout_logfile=/var/log/thing.log
autostart=true
autorestart=true
startsecs=10
redirect_stderr=true
directory=/
startretries=1000

How can I avoid repetition of identical settings?

I have an S3 bucket as a resource in my CloudFormation template, with DeletionPolicy set to Retain. This works as expected: when deleting the stack, it does indeed retain the bucket. However, when I attempt to create the stack again, creation fails while attempting to create the same bucket again, with an error message complaining that it already exists.

What do I need to add to my CloudFormation template to make it not try recreating a resource which already exist?

Relevant fragment of my template is as follows:

      "Resources": {
        "SomeS3Bucket" : {
          "Type" : "AWS::S3::Bucket",
          "DeletionPolicy" : "Retain",
          "Properties": {
              "BucketName": "SomeS3Bucket"
              }
          }

I'm looking for a solution to mirror or replicate one directory (or one filesystem) across a few Linux servers. Ideal solution would be one, which permits all servers read-write access. I also want it to me resilient, if one of the servers goes down, rest should still work w/o loosing any data at all.

I've been looking at some solutions:

• DRBD: block level replications, seems a bit overkill;
• lsyncd: looks very simple, but I have doubts about performance;
• GlusterFS: seems like that would be a good match, haven't figured out yet how exactly the replication mode works. Will it have characteristics I require?

Any other suggestions are welcome.

I would like to share EBS backed file system of size up to 20GB in 200K files across multiple EC2 instances. Master-master would be ideal, but I'd be happy with master-slave solution too.

I know that generic Linux solution would be to use DRBD, but is there some tool specific to AWS for that?

BTW. I've found similar question that was asked over a year ago: Sharing / replicating EBS across AWS nodes

I've got table with following schema:

CREATE TABLE `tblsomething` (
  `something_id` int(11) NOT NULL AUTO_INCREMENT,
   …
 PRIMARY KEY (`something_id`)
) ENGINE=InnoDB AUTO_INCREMENT=144620955 

I need to drop the auto increment. So I'm thinking to do:

ALTER TABLE tblsomething MODIFY something_id int NOT NULL;

But this part of MySQL doc worries me:

In most cases, ALTER TABLE works by making a temporary copy of the original table. The alteration is performed on the copy, and then the original table is deleted and the new one is renamed. While ALTER TABLE is executing, the original table is readable by other sessions. Updates and writes to the table are stalled until the new table is ready, and then are automatically redirected to the new table without any failed updates.

So is dropping auto increment actually one of these cases? Will it lock up my table?

What is the best way to share directories between Windows Vista host and Linux guest on VMPlayer?

The scenario is following:

• on the Windows host I've got development tools (IDE, etc.);
• on virtualized Linux I've got the test environment;
• I need to share code directory between the two;
• I'd prefer to have files served from Win to Lin, but if the other way around is more efficient, I consider switching.

Edit: should I use cifs rather then smbfs?

Edit2: Ok, my initial question was because I've done it "by the book". Mounted with smbmount. Was terribly slow, unusable. Then I've mounted with cifs. Didn't help. Now I've tried the ip option as suggested by Evan. No change. Is it about round trips to domain controller or something like that? Should I set up local account just for sharing?

Per GB prices of rapid SSD (like Intel X25-E) come close to prices of high-end RAM. So what extra advantages does SSD give you? What are particular reasons, why you buy SSD, instead of just putting more RAM in your server machine, to have it used as HDD cache or even create RAM-disk?

EDIT: of course I'm aware, that SSD are persistent. But so is the data in disk cache. Reading from RAM has got to be a lot faster, then reading from SSD. Also, SSD have slow write times, so no advantage over HDD there. Especially for sequential writes.

EDIT2: amount of RAM you can put is not so limited. With introduction of DDR3, it's not multiple of 2 anymore, it's multiple of 3. Standard SOHO MoBos have 6 slots, while server boards have 12 or even impressive 18 slots, supporting total of 144GB of RAM. Even if you use more cost effective 4GB memory sticks, you still can have 72GB.