From f14a8404cb5386c954b3ad531eeb5ad072d62516 Mon Sep 17 00:00:00 2001 From: Andrea Mazzoleni Date: Sat, 1 Nov 2014 18:13:09 +0100 Subject: [PATCH] Some clearification about wasted space in the manual. --- snapraid.1 | 11 ++++++----- snapraid.d | 11 ++++++----- snapraid.txt | 11 ++++++----- 3 files changed, 18 insertions(+), 15 deletions(-) diff --git a/snapraid.1 b/snapraid.1 index 03ff0639..c6353cae 100644 --- a/snapraid.1 +++ b/snapraid.1 @@ -665,7 +665,7 @@ Schedules a rehash of the whole array. .PP This option can be used to change the hash kind used, typically when upgrading from a 32 bits system to a 64 -bits one to switch from MurmurHash3 to the faster SpookyHash. +bits one, to switch from MurmurHash3 to the faster SpookyHash. .PP If you are already using the optimal hash, this command do nothing and tells you that nothing has to be done. @@ -996,7 +996,7 @@ specifications. This option can be used many times. .SS blocksize SIZE_IN_KIBIBYTES Defines the basic block size in kibi bytes of the parity. -One kibi bytes is 1024 bytes. The default is blocksize is 256 +One kibi bytes is 1024 bytes. The default blocksize is 256 and it should work for most cases. .PP A reason to use a different blocksize is if your system has less @@ -1031,6 +1031,10 @@ wasted for each file. For example, with 100000 files and a 256 KiB block size, you are going to waste 12 GiB of parity, that may result in 12 GiB less space available in the data disk. .PP +You can get the amount of wasted space in each disk using the \[dq]status\[dq] +command. This is the amount of space that you must leave free in the data +disks, or use for files not included in the array. +.PP To avoid to problem, you can use a bigger partition for parity. For example, if you have the parity partition bigger than 12 GiB than data disks, you have enough extra space to handle up to 100000 @@ -1049,9 +1053,6 @@ mkfs.ext4 \-m 0 \-T largefile4 DEVICE This results in about 1.5% of extra space. Meaning about 48 GiB for a 3 TiB disk, that allows about 400000 files in each data disk without any wasted space. -.PP -Note also, that any file in data disks that is excluded from the parity -computation, counts for its size as extra parity space for such data disk. .SS autosave SIZE_IN_GIBIBYTES Automatically save the state when syncing after the specified amount of GiB processed. diff --git a/snapraid.d b/snapraid.d index 8aed6957..13c20f84 100644 --- a/snapraid.d +++ b/snapraid.d @@ -427,7 +427,7 @@ Commands This option can be used to change the hash kind used, typically when upgrading from a 32 bits system to a 64 - bits one to switch from MurmurHash3 to the faster SpookyHash. + bits one, to switch from MurmurHash3 to the faster SpookyHash. If you are already using the optimal hash, this command do nothing and tells you that nothing has to be done. @@ -762,7 +762,7 @@ Configuration blocksize SIZE_IN_KIBIBYTES Defines the basic block size in kibi bytes of the parity. - One kibi bytes is 1024 bytes. The default is blocksize is 256 + One kibi bytes is 1024 bytes. The default blocksize is 256 and it should work for most cases. A reason to use a different blocksize is if your system has less @@ -794,6 +794,10 @@ Configuration block size, you are going to waste 12 GiB of parity, that may result in 12 GiB less space available in the data disk. + You can get the amount of wasted space in each disk using the "status" + command. This is the amount of space that you must leave free in the data + disks, or use for files not included in the array. + To avoid to problem, you can use a bigger partition for parity. For example, if you have the parity partition bigger than 12 GiB than data disks, you have enough extra space to handle up to 100000 @@ -808,9 +812,6 @@ Configuration a 3 TiB disk, that allows about 400000 files in each data disk without any wasted space. - Note also, that any file in data disks that is excluded from the parity - computation, counts for its size as extra parity space for such data disk. - autosave SIZE_IN_GIBIBYTES Automatically save the state when syncing after the specified amount of GiB processed. diff --git a/snapraid.txt b/snapraid.txt index dc991fd3..bacd2581 100644 --- a/snapraid.txt +++ b/snapraid.txt @@ -469,7 +469,7 @@ Schedules a rehash of the whole array. This option can be used to change the hash kind used, typically when upgrading from a 32 bits system to a 64 -bits one to switch from MurmurHash3 to the faster SpookyHash. +bits one, to switch from MurmurHash3 to the faster SpookyHash. If you are already using the optimal hash, this command do nothing and tells you that nothing has to be done. @@ -826,7 +826,7 @@ This option can be used many times. ------------------------------- Defines the basic block size in kibi bytes of the parity. -One kibi bytes is 1024 bytes. The default is blocksize is 256 +One kibi bytes is 1024 bytes. The default blocksize is 256 and it should work for most cases. A reason to use a different blocksize is if your system has less @@ -858,6 +858,10 @@ wasted for each file. For example, with 100000 files and a 256 KiB block size, you are going to waste 12 GiB of parity, that may result in 12 GiB less space available in the data disk. +You can get the amount of wasted space in each disk using the "status" +command. This is the amount of space that you must leave free in the data +disks, or use for files not included in the array. + To avoid to problem, you can use a bigger partition for parity. For example, if you have the parity partition bigger than 12 GiB than data disks, you have enough extra space to handle up to 100000 @@ -872,9 +876,6 @@ This results in about 1.5% of extra space. Meaning about 48 GiB for a 3 TiB disk, that allows about 400000 files in each data disk without any wasted space. -Note also, that any file in data disks that is excluded from the parity -computation, counts for its size as extra parity space for such data disk. - ---- 7.8.1 autosave SIZE_IN_GIBIBYTES ---- Automatically save the state when syncing after the specified amount of GiB processed.