1、unlocking condition

unlocking condition發(fā)音

英：　　美：

unlocking condition中文意思翻譯

常見(jiàn)釋義：

解鎖條件

unlocking condition雙語(yǔ)使用場(chǎng)景

1、Unlocking the mutex happens immediately, but waiting on the condition mycond is normally a blocking operation, meaning that our thread will go to sleep, consuming no CPU cycles until it is woken up.───對互斥對象解鎖會(huì )立即發(fā)生，但等待條件mycond通常是一個(gè)阻塞操作，這意味著(zhù)線(xiàn)程將睡眠，在它蘇醒之前不會(huì )消耗CPU周期。

unlocking condition相似詞語(yǔ)短語(yǔ)

1、dry condition───干工況

2、condition───n.條件；情況；環(huán)境；身份；vt.決定；使適應；使健康；以…為條件

3、operating condition───運行狀態(tài)，運行條件；操作規范；運行條件，運轉狀態(tài); 工作狀況[條件]; 操作規范[條件]; 操縱[控制]條件

4、unlocking potential───釋放潛能

5、unlocking───n.開(kāi)鎖；開(kāi)放；adj.開(kāi)鎖的；v.開(kāi)鎖（unlock的ing形式）

6、rare condition───罕見(jiàn)的情況

7、unlocking mechagon───解鎖機械

8、unlocking mechagnomes───解鎖機械磁鐵

9、unlocking nightborne───解鎖夜航

2、proxmox ve -- ZFS on Linux 2019-08-30

ZFS是由Sun Microsystems設計的一個(gè)文件系統和邏輯卷管理器的組合。從proxmox ve 3.4開(kāi)始，zfs文件系統的本機Linux內核端口作為可選文件系統引入，并作為根文件系統的附加選擇。不需要手動(dòng)編譯ZFS模塊-包括所有包。

通過(guò)使用zfs，它可以通過(guò)低硬件預算花銷(xiāo)實(shí)現最大的企業(yè)功能，并且可以通過(guò)利用SSD緩存或純使用SSD來(lái)實(shí)現高性能系統。ZFS可以通過(guò)適度的CPU和內存負載以及簡(jiǎn)單的管理來(lái)取代成本高昂的硬件RAID卡。

General ZFS advantages

ZFS很大程度上依賴(lài)于內存，因此至少需要8GB才能啟動(dòng)。在實(shí)踐中，盡可能多地使用高配置硬件。為了防止數據損壞，我們建議使用高質(zhì)量的ECC RAM。

如果使用專(zhuān)用緩存和/或日志磁盤(pán)，則應使用企業(yè)級SSD（例如Intel SSD DC S3700系列）。這可以顯著(zhù)提高整體性能。

If you are experimenting with an installation of Proxmox VE inside a VM (Nested Virtualization), don’t use virtio for disks of that VM, since they are not supported by ZFS. Use IDE or SCSI instead (works also with virtio SCSI controller type).

When you install using the Proxmox VE installer, you can choose ZFS for the root file system. You need to select the RAID type at installation time:

| RAID0

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Also called “striping”. The capacity of such volume is the sum of the capacities of all disks. But RAID0 does not add any redundancy, so the failure of a single drive makes the volume unusable.

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| RAID1

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Also called “mirroring”. Data is written identically to all disks. This mode requires at least 2 disks with the same size. The resulting capacity is that of a single disk.

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| RAID10

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A combination of RAID0 and RAID1. Requires at least 4 disks.

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| RAIDZ-1

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A variation on RAID-5, single parity. Requires at least 3 disks.

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| RAIDZ-2

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A variation on RAID-5, double parity. Requires at least 4 disks.

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| RAIDZ-3

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A variation on RAID-5, triple parity. Requires at least 5 disks.

|

The installer automatically partitions the disks, creates a ZFS pool called rpool, and installs the root file system on the ZFS subvolume rpool/ROOT/pve-1.

Another subvolume called rpool/data is created to store VM images. In order to use that with the Proxmox VE tools, the installer creates the following configuration entry in /etc/pve/storage.cfg:

zfspool: local-zfs

pool rpool/data

sparse

content images,rootdir

After installation, you can view your ZFS pool status using the zpool command:

# zpool status

pool: rpool

state: ONLINE

scan: none requested

config:

errors: No known data errors

The zfs command is used configure and manage your ZFS file systems. The following command lists all file systems after installation:

# zfs list

NAME USED AVAIL REFER MOUNTPOINT

rpool 4.94G 7.68T 96K /rpool

rpool/ROOT 702M 7.68T 96K /rpool/ROOT

rpool/ROOT/pve-1 702M 7.68T 702M /

rpool/data 96K 7.68T 96K /rpool/data

rpool/swap 4.25G 7.69T 64K -

Depending on whether the system is booted in EFI or legacy BIOS mode the Proxmox VE installer sets up either grub or systemd-boot as main bootloader. See the chapter on Proxmox VE host bootladers for details.

This section gives you some usage examples for common tasks. ZFS itself is really powerful and provides many options. The main commands to manage ZFS are zfs and zpool. Both commands come with great manual pages, which can be read with:

# man zpool

To create a new pool, at least one disk is needed. The ashift should have the same sector-size (2 power of ashift) or larger as the underlying disk.

zpool create -f -o ashift=12

To activate compression

zfs set compression=lz4

Minimum 1 Disk

zpool create -f -o ashift=12

Minimum 2 Disks

zpool create -f -o ashift=12 mirror

Minimum 4 Disks

zpool create -f -o ashift=12 mirror mirror

Minimum 3 Disks

zpool create -f -o ashift=12 raidz1

Minimum 4 Disks

zpool create -f -o ashift=12 raidz2

It is possible to use a dedicated cache drive partition to increase the performance (use SSD).

As it is possible to use more devices, like it’s shown in "Create a new pool with RAID*".

zpool create -f -o ashift=12 cache

It is possible to use a dedicated cache drive partition to increase the performance(SSD).

As it is possible to use more devices, like it’s shown in "Create a new pool with RAID*".

zpool create -f -o ashift=12 log

If you have an pool without cache and log. First partition the SSD in 2 partition with parted or gdisk

| Always use GPT partition tables. |

The maximum size of a log device should be about half the size of physical memory, so this is usually quite small. The rest of the SSD can be used as cache.

zpool add -f log cache

Changing a failed device

zpool replace -f

Changing a failed bootable device when using systemd-boot

sgdisk -R

sgdisk -G

zpool replace -f

pve-efiboot-tool format

pve-efiboot-tool init

| ESP stands for EFI System Partition, which is setup as partition #2 on bootable disks setup by the Proxmox VE installer since version 5.4. For details, see Setting up a new partition for use as synced ESP . |

ZFS comes with an event daemon, which monitors events generated by the ZFS kernel module. The daemon can also send emails on ZFS events like pool errors. Newer ZFS packages ships the daemon in a separate package, and you can install it using apt-get:

# apt-get install zfs-zed

To activate the daemon it is necessary to edit /etc/zfs/zed.d/zed.rc with your favourite editor, and uncomment the ZED_EMAIL_ADDR setting:

ZED_EMAIL_ADDR="root"

Please note Proxmox VE forwards mails to root to the email address configured for the root user.

| The only setting that is required is ZED_EMAIL_ADDR. All other settings are optional. |

It is good to use at most 50 percent (which is the default) of the system memory for ZFS ARC to prevent performance shortage of the host. Use your preferred editor to change the configuration in /etc/modprobe.d/zfs.conf and insert:

options zfs zfs_arc_max=8589934592

This example setting limits the usage to 8GB.

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If your root file system is ZFS you must update your initramfs every time this value changes:

update-initramfs -u

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Swap-space created on a zvol may generate some troubles, like blocking the server or generating a high IO load, often seen when starting a Backup to an external Storage.

We strongly recommend to use enough memory, so that you normally do not run into low memory situations. Should you need or want to add swap, it is preferred to create a partition on a physical disk and use it as swapdevice. You can leave some space free for this purpose in the advanced options of the installer. Additionally, you can lower the “swappiness” value. A good value for servers is 10:

sysctl -w vm.swappiness=10

To make the swappiness persistent, open /etc/sysctl.conf with an editor of your choice and add the following line:

vm.swappiness = 10

Table 1. Linux kernel swappiness parameter values

vm.swappiness = 0

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The kernel will swap only to avoid an out of memory condition

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vm.swappiness = 1

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Minimum amount of swapping without disabling it entirely.

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vm.swappiness = 10

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This value is sometimes recommended to improve performance when sufficient memory exists in a system.

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vm.swappiness = 60

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The default value.

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vm.swappiness = 100

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The kernel will swap aggressively.

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ZFS on Linux version 0.8.0 introduced support for native encryption of datasets. After an upgrade from previous ZFS on Linux versions, the encryption feature can be enabled per pool:

# zpool get feature@encryption tank

NAME PROPERTY VALUE SOURCE

tank feature@encryption disabled local

NAME PROPERTY VALUE SOURCE

tank feature@encryption enabled local

| There is currently no support for booting from pools with encrypted datasets using Grub, and only limited support for automatically unlocking encrypted datasets on boot. Older versions of ZFS without encryption support will not be able to decrypt stored data. |

| It is recommended to either unlock storage datasets manually after booting, or to write a custom unit to pass the key material needed for unlocking on boot to zfs load-key. |

| Establish and test a backup procedure before enabling encryption of production data.If the associated key material/passphrase/keyfile has been lost, accessing the encrypted data is no longer possible. |

Encryption needs to be setup when creating datasets/zvols, and is inherited by default to child datasets. For example, to create an encrypted dataset tank/encrypted_data and configure it as storage in Proxmox VE, run the following commands:

# zfs create -o encryption=on -o keyformat=passphrase tank/encrypted_data

Enter passphrase:

Re-enter passphrase:

All guest volumes/disks create on this storage will be encrypted with the shared key material of the parent dataset.

To actually use the storage, the associated key material needs to be loaded with zfs load-key:

# zfs load-key tank/encrypted_data

Enter passphrase for 'tank/encrypted_data':

It is also possible to use a (random) keyfile instead of prompting for a passphrase by setting the keylocation and keyformat properties, either at creation time or with zfs change-key on existing datasets:

# dd if=/dev/urandom of=/path/to/keyfile bs=32 count=1

| When using a keyfile, special care needs to be taken to secure the keyfile against unauthorized access or accidental loss. Without the keyfile, it is not possible to access the plaintext data! |

A guest volume created underneath an encrypted dataset will have its encryptionroot property set accordingly. The key material only needs to be loaded once per encryptionroot to be available to all encrypted datasets underneath it.

See the encryptionroot, encryption, keylocation, keyformat and keystatus properties, the zfs load-key, zfs unload-key and zfs change-key commands and the Encryption section from man zfs for more details and advanced usage.