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SSD aligning on GPT and Filesytem Choices For SSD

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March 12, 2012 7:55:13 PM

It drives me crazy, i can not work, i can not sleep at night. Some says you have to do heavy math for calculating SSD, some say it is made automatically. I am very much confused right now. Here is the deal:

I bought an SSD and HDD for my new UEFI based system.

SSD -> OCZ Vertex-3 120 GB

HDD -> Western Digital Caviar Black 1 TB

I will use SSD to install Archlinux and Window 7 64 bit on a GPT based system. HDD will be only used to store data(music, videos etc...).

My partition table on SSD will be like this:

400 MiB -> UEFI Partititon
100 MiB -> /boot (EXT4, was using EXT2 before) (GRUB2 Boot Partition)
50 GiB -> Windows 7 (NTFS)
10 GiB -> / (EXT-4)
5 GiB -> /var (EXT-4) (Was using Reiserfs before for small file performance)
40 GiB-> /home (EXT-4)
Swap -> No Swap, I have 8 GB RAM

1-) Is it beneficial to align HDD too? Is it different from SSD?

2-) When aligning SSD, just creating partitions using gdisk will work automatically? Or i should go and learn about Erase block sizes, sectors, etc and make some math on them.

3-) Is no swap a good idea?

4-) Is making /boot EXT2 instead of EXT4 helps for speed?

5-) Similar to above, is making /var Reiserfs instead of EXT4 helps for speed? (Ony Ext4 -excluding BRTFS- supports TRIM?)
a b G Storage
March 13, 2012 12:44:47 AM

SSDs are still treated like rotating disk from an alignment perspective. Normally you want your offset to be divisible evenly by your block size so that any invidual block read corresponds to a single block read on "disk".
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March 13, 2012 6:39:39 AM

tokencode said:
SSDs are still treated like rotating disk from an alignment perspective. Normally you want your offset to be divisible evenly by your block size so that any invidual block read corresponds to a single block read on "disk".

Thank you. Can you direct me to articles about SSD, why we need aligning, what is aligning. Long word short i want to know everything in detail, so i can clearly understand.

Especially not about this particulalr matter but... I read and understand about rotating hard disk's sector and tracks. But didn't understand the cylinders. Because it is just same sectors on different tracks. So what is the deal? How can it benefit to us? The benefit of track and sector is obvious, but cylinder?
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a b G Storage
March 13, 2012 8:33:36 AM

Cylinders apply when you have multiple platters in an HDD, each platter has a head so if you have 3 platters and 3 heads, the 3 sectors (1 on each platter) that are in the same position form the cylinder. You can read all 3 sectors at once without moving the head.

I didn't have an article to refer you to but since the SSDs essentially emulate a traditional hdd, they use the same logic in retrieving data. Even though there is no disk rotating or heads etc, the storage is still carved up into "sectors", setting your offset garentees you only need to read form 1 sector to retrieve data in a block of lesser or equal size.
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March 13, 2012 10:20:15 AM

Aren't the heads independent of each other? What is the difference if they are on the same position or not?

Oh, maybe it is about the way they work? How is data written to platters. Let's say we have 3 platters. Is it like this:

The first sector on the platter 1 is sector 1. And the final sector on the first platter is let's say 120.

Then if it the first platter became full, it starts to write to second platter.
The first sector on the platter 2 is sector 121?
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