Does "Round to Cylinders" matter in partitioning ?

[benali72]

I notice that many versions of GParted have a checkbox for "Round to cylinders." By default, it is selected.

I've found it much easier to read the partition list output of GParted if you do not round to cylinders, because if you leave it On you get a lot of 1 or 2 MiB unallocated space between partitions.

Are there any situations where it is good -- or required -- to "round to cylinders" ?

Thanks for your feedback.

[Ted Dog]

yes..

[8-bit]

I have also been curious about this.
Can you steer us to some references that explain why it matters?

[gcmartin]

Well, this might help. We all know HDD architecture is in cylinders. Microsoft, with its partitioning tools allocated space to the nearest block in Miegabytes, while Unix and IBM allocated along the lines of cylinders as it had some advantages in the SCSI architecture for I/O traffic and data alignment.

If you're looking for a recommendation, I've not seen one, except from some Enterprise Vendors in years past favoring cylinders in their I/O solutions delivery.

With the increased use of these later memory I/O devices such as USB sticks and SSDs, this may be a good question for testing if we cannot find any reports of tests. The concept of cylinder versus MB just might have a performance difference, a partition storage size difference, or a data blocking difference or .... Further, there may be a data recovery impact...maybe.

Review the GParted option for this selection of cylinder vs MB partitioning
Hope this helps

[anikin]

I notice that many versions of GParted have a checkbox for "Round to cylinders." By default, it is selected

First of all, you should not use many versions. The developer of GParted strongly insists on using only the latest version. For obvious reasons - its development is fluid, bugs are identified and eliminated, the program is continuously improved. As an example, see this excerpt from the latest release announcement - version 18.01:

Fix partition size less than ext2/3/4, ntfs, reiserfs file system
Prevent crash when creating new partition on disk with loop label
Fix default partition table can not handle > 2 TiB disks
Add BitLocker disk encryption detection

And here's a quick research on what versions distros are offering:
Ubuntu
raring - 0.12.1-2 (Barry's raring - 0.14)
saucy - 0.16.1-1
trusty - 0.18.0-1
Debian
squeeze - 0.7.0-1
wheezy - 0.12.1-2
jessie (testing) - 0.18.0-1
sid (unstable) - 0.18.0-1
Slackware 14.1 - 0.16.1

Mostly, they are hopelessly outdated and useless. However, that is not a big deal and we shouldn't be worried at all. Suppose your Puppy suddenly can't boot - GParted to rescue, of course ... but it's installed in Puppy ... I always keep the latest version either on a flash drive or a CD. If worst comes to worst, I won't be left completely disarmed. Besides, GParted is an excellent live CD, with a simple browser that will get you online, should you need help.

Does "Round to Cylinders" matter in partitioning ?

It does matter a lot and it's all about partition alignment, which in turn is about hard disk geometry and that is a huge subject. It can't be covered in forum post. Do a Google search, there's no shortage of info. Recently, user mcewanw posted this link in another thread: http://www.thomas-krenn.com/en/wiki/Partition_Alignment that will give you some insight in condensed form. And here's required reading: http://gparted.org/display-doc.php?name=help-manual.

Are there any situations where it is good -- or required -- to "round to cylinders"?

To specify the alignment of the partition, click the Align to arrow button, and select from the list.

Use MiB alignment for modern operating systems. This setting aligns partitions to start and end on precise mebibyte (1,048,576 byte) boundaries. MiB alignment provides enhanced performance when used with RAID systems and with Solid State Drives, such as USB flash drives.

Use Cylinder alignment to maintain compatibility with operating systems released before the year 2000, such as DOS. This setting aligns partitions to start and end on disk cylinder boundaries.
Tip

The Cylinder/Head/Sector values reported by modern disk devices no longer have a direct physical relationship to the data stored on the disk device. Hence it is no longer valid to use this alignment setting to achieve enhanced performance.

Use None only if you have an in-depth knowledge of disk structure, partition tables, and boot records. This setting places partition boundaries relative to the end of any immediately preceding partition on the disk device. This setting is not guaranteed to reserve or respect space required for boot records.

Which means, go with MiB, if that won't boot (unlikely), align to cylinder.

[8-bit]

I remember having an error once, not on Puppy but on an IBM compatible of possible loss of data due to partition overlap. And this problem I believe was caused by not having partitions start and end on cylinder boundaries.

So to me, depending on the hard drive, one risks partition overlap and loss of data if the partition is created without starting and ending on cylinder boundaries.

That is about as good of an explanation as I can give without reading the links.

[Sky Aisling]

Perhaps this is an appropriate place for this question. My apologies if it isn't.

My question is about the symbol in the tray (panel) that shows a stack of disk cylinders.
Some of my Puppy setups show the top cylinder activated.
Some of my Puppy setups show the bottom cylinders activated.
Does this have something to do with how I've placed the partitions on the drive?

If so, it would seem like it would be wise to locate the .iso and/or data in a lower cylinder, one that isn't used as much as the first cylinder.
Cylinders do ware out after a while.

[benali72]

Thanks for the good advice. I'll stick to rounding to cylinders.

[anikin]

The good advice comes from the link and GParted manual.
My point is partitioning is an exact science and should be based on solid knowledge not on forum speculation. Here's a link, that offers such knowledge: http://www.tldp.org/HOWTO/html_single/Partition/

And some good news:

The GParted team is proud to announce another stable release of GParted Live.

This live image fixes a bug with the ssh host key protocol ed25519 not being generated during boot. Thanks goes to Alexandros Manoussakis for discovering this bug and suggesting some additional commands.

Items of note include:

Based on the Debian Sid repository (as of 2014/Apr/10)
Updated Linux kernel to 3.13.7-1
Updated grub to 2.02~beta2-8
Added the following commands:
screen - screen manager with VT100/ANSI terminal emulation
rsync - a fast, versatile, remote (and local) file-copying tool
ping - check network connectivity to another host on a network
telnet - communicate with another host using the TELNET protocol
traceroute - print the route packets trace to network host
bc - an arbitrary precision calculator language

Thanks goes to Steven Shiau for building this live image.

Curtis

http://gparted.org/livecd.php
http://gparted.org/download.php