Ceph failure domain

 

cephx; customize-failure-domain: (boolean) Setting this to true will tell Ceph to replicate across Juju's Availability Zone instead of specifically by host . The process  Set the ruleset failure domain to osd (instead of the host which is the default):. Important. sh -d -n -X -l mon osd >>>> ceph osd erasure-code-profile set profile33 ruleset-failure-domain=osd >>>> k=3 m=3 >>>> ceph osd crush rule create-erasure ecruleset33 profile33 >>>> ceph osd pool create testec-33 20 20 erasure profile33 ecruleset33 >>>> . I managed a 1400 osd cluster that would lose 1-3 drives in random nodes when I added new storage due  25 Apr 2015 buckets: Once you define bucket types, you must declare bucket instances for your hosts, and any other failure domain partitioning you choose. For example, to address the possibility of concurrent failures, it may be desirable to ensure that data replicas are on devices using different  Oct 19, 2015 However, capturing the host as a failure domain is preferred if you need to power down the host to change a drive (assuming it's not hot-swappable). Ceph is able to enable hyperscale storage via CRUSH, a hash-based algorithm for  Ceph supports the ability to organize placement groups, which provide data mirroring across OSDs, so that high-availability and fault-tolerance can be maintained even in the event of a rack or site outage. The CRUSH placement algorithm is used to allow failure domains to be defined across hosts, racks, rows, or datacenters, depending  Nov 8, 2017 When enabling customize-failure-domain config option for charm-ceph-osd when deploying Ceph Luminous (available in UCA Pike), the charm uses the "osd crush location" configuration option in the ceph. It is possible to define failure domain at the level of: disk, server and rack defining the CRUSH map that contains a  This innovative architecture minimize the failure domain to a disk unit instead of many disks become un-accessible in one server for many disk architecture. conf file and set rbd_default_features = 1 under the [global] section before going any further. Failure to do so  Reference Architecture: Deploying Red Hat Ceph Storage Clusters Based on Supermicro Storage Servers . 25 Oct 2016 - 38 min - Uploaded by OpenStack FoundationIn this presentation, we discuss best practices and performance tuning for OpenStack cloud 18 Jun 2015 - 62 min - Uploaded by Southern California Linux ExpoCeph is designed around the assumption that all components of the system ( disks, hosts Ceph can distribute data replicas so that in the event of a failure in one failure domain (e. , a rack). 2. 5. 3. ceph. To modify a profile, you must create a new pool with a different profile  2. g. com/docs/master/rados/deployment/ceph-deploy-osd/ It says (under "Prepare OSDs"): "Note: When running multiple Ceph OSD daemons on a single node, and sharing a partioned journal with each OSD daemon, you should consider the entire node the minimum failure domain for  24 Feb 2015 By default, the failure domain is set to host, and pool size and min-size is set to 3 and 2 respectively. Storage cluster is scale out by connection Mars storage servers by top of the rack Ethernet switch. Consensus among various monitor instances ensures consistent. If you do not want CRUSH to automatically rebalance the  These rules also enforce availability policies; for example, replicas must not be in the same rack or other defined failure domain in the data center. The equivalent command line parameter for this is erasure-code-directory=<directory_path> Default value = /usr/lib64/ceph/erasure-code ruleset-failure-domain ===> Defines the failure domain , you should set it as  DYNAMIC DATA PLACEMENT. "Periodically, you may need to perform maintenance on a subset of your cluster, or resolve a problem that affects a failure domain (e. ○ failure under 2x replication. PERFORMANCE DOMAINS. ○ power circuits. Failure Domains. Leaf spine networks are typically moving away from pure layer 2 topology, where layer 2 domain is terminated on the leaf switches and layer 3 routing is done With Ceph, there is an underlying assumption that complete failure of a section of your infrastructure, be that a disk, node, or even rack should be considered as  In the Ceph docs, at: http://docs. ○ replicas from one device are spread across many other devices. 4. This is fact. failure. Installing and Configuring Ceph. 30 Apr 2016 In this configuration each node is a new failure domain. /rados --pool testec-33 put SOMETHING  29 Feb 2016 An EC pool of 4+2 chunks on a ceph cluster with a failure domain set to "host", a minimum of 6 hosts with OSDs will be needed, as we do not have 6 hosts we need to use “osd” as the failure domian which will help us to get the data striped across disks rather than hosts. The process  Set the ruleset failure domain to osd (instead of the host which is the default):. There are cases with high density systems where you have multiple nodes in the same chassis. This approach is known as replica-based data protection. You can have drives in a "ready-to-fail" state that doesn't show up in SMART or anywhere easy to track. CHAPTER 5. ○ Deploy usually it's not so easy (port 22 closed). CRUSH LOCATION. Basically it comes down to replication size and min_size plus CRUSHMAP configuration and failure domains. Anything, if exposed to a long enough time period, will fail. Rules: Rules consist of the manner of selecting buckets. A CRASH COURSE IN CRUSH Sage Weil Ceph Principal Architect 2016-06-29; 2. Objects hash(oid) & mask pgid. So you might opt for a higher minimum failure domain in a  CRUSH maps provide the physical topology of the cluster to the CRUSH algorithm to determine where the data for an object and its replicas should be stored, and how to do so across failure domains for added data safety among other things. VSM manages the placement of  3 Jun 2016 Odd number (at least 3) of monitors; Each monitor on a separate server within a separate failure domain; At least 16GB RAM; At least 100GB disk, SSD for big clusters. ADD A BUCKET. failure domain). (ino,ono) oid. 1. Creating the RBD image. When you initially set up a test cluster,  The CRUSH Map: Contains a list of storage devices, the failure domain hierarchy (e. REMOVE A BUCKET. Traditional block based file systems can  19 Dec 2014 Ceph - strong geo-replication. PGs. Ceph automatically rebalances data appropriately, immediately using all  same failure domain. ○ You need performant link between involved sites (low latency). 1. This awareness of failure domains during data place- ment is critically important for the overall data safety of very large storage systems where correlated failures are common. ), and rules for traversing the hierarchy when storing data. libs k=2 m=1 plugin=jerasure ruleset-failure-domain=host technique=reed_sol_van. Note - You really should go into your cepf. OUTLINE ○ Ceph ○ RADOS ○ CRUSH functional placement ○ CRUSH hierarchy and failure domains ○ CRUSH rules ○ CRUSH in practice ○ CRUSH internals ○ CRUSH tunables ○  4 Jul 2014 A datacenter containing three hosts of a non profit Ceph and OpenStack cluster suddenly lost connectivity and it could not be restored within 24h. For participating in the task of data management and lookup, both the Ceph client and Ceph OSD should be  12 Sep 2013 CAP – The unremitting truth of the CAP theorem. File. ADDING AN OSD TO  7 Nov 2014 And the operator can change the failure domain with the ruleset-failure-domain parameters. By reflecting the underlying physical organization of the Ceph Storage Cluster, CRUSH can model—and thereby address—potential sources of correlated device failures. com/docs/jewel/rados/troubleshooting/troubleshooting-osd/#stopping-w-out-rebalancing. ceph-osd/0. For example, in a 3-Replica configuration, you should consider three cabinets as three different failure domains, and store a replica in each one of those. We operate our cluster under default CRUSHMAP with the host as a  Apr 30, 2016 In this configuration each node is a new failure domain. CEPH OSDS IN CRUSH. Following is an example of a leaf spine toplogy. conf] osd crush location = root=default juju_availability_zone=zone-rack01 host=node01 However, I cannot find any rack or  The out-of-the-box Ceph deployment requires 3 hosts with at least one block device on each host that can be dedicated for sole use by Ceph. See CRUSH Maps for additional details. By defining failure-domains, such as a Rack of  29 Jun 2016 A crash course in CRUSH. ○ separate replicas across failure domains. loss of TOR switch), replica data can be accessed from another failure domain. Easily expandable with scale-out behavior – We can simply add more storage servers to the cluster to gain more space. The CRUSH algorithm enables the Ceph Storage Cluster to scale, rebalance, and recover dynamically. Meets minimum fault domain recommendation (single . Set the ruleset failure domain to osd (instead of the host which is the default): $ ceph osd erasure-code-profile set myprofile \ crush-failure-domain=osd $ ceph osd erasure-code-profile get myprofile k=2 m=1 plugin=jerasure technique=reed_sol_van crush-failure-domain=osd $ ceph osd pool create ecpool 12 12 erasure  1 Sep 2017 Don't discount failing drives. Choosing the right profile is important because it cannot be modified after the pool is created: a new pool with a different profile needs to be created and all objects from the previous pool  16 Apr 2012 placement and data safety. Having multiple object replicas (or M coding chunks) helps preventing data loss, but it is not sufficient to address high availability. This provides consistent hop latency and bandwidth. A few examples of different crush maps and cluster configurations are explained below: table. CHAPTER 4. ○ Exploit CRUSH map and placement rules to define extra datacenter failure domains and placement strategies  Apr 8, 2014 In most of the cases this parameter is automatically added once you define plugin name . To modify a profile, you must create a new pool with a different profile  Dec 19, 2014 Ceph - strong geo-replication. Ceph uti- lizes a highly adaptive distributed metadata . However, a pool that was  20 Apr 2017 juju debug-log -i unit-ceph-osd-0 --replay] unit-ceph-osd-0: 15:34:29 INFO unit. This is usually handled by the software coordinating the cluster via copies of all data on at least two nodes. The Ceph pool dedicated to this datacenter became unavailable as expected. juju-log mon:63: AZ Info: juju_availability_zone=zone-rack01 [/etc/ceph/ceph. When backfilling, the drive is using sectors it may not normally use. A Ceph installation requires at least one monitor, one OSD, and one meta- data server. CRUSH HIERARCHIES. libs k=2 m=1 plugin= jerasure ruleset-failure-domain=host technique=reed_sol_van. com/docs/master/rados/operations/erasure-code-jerasure/ > let 's take an example: my failure domain is composed by 3 rooms, so usually, in a  If "none" is specified, keys will still be created and deployed so that it can be enabled later. These numbers are generally larger than the numbers provided on the official Ceph  ceph osd erasure-code-profile get default directory=. Figure 3: Files are striped across many objects, grouped into placement groups (PGs),  12 Jul 2016 CRUSH maps provide the physical topology of the cluster to the CRUSH algorithm to determine where the data for an object and its replicas should be stored, and how to do so across failure domains for added data safety among other things. By encoding this information into the cluster map, CRUSH placement policies can separate object replicas across different failure domains while still maintaining the desired distribution. Here's a quick tutorial on how to make RBD's, disable their features, and make them persistent at startup. conf file. Objects hash(oid) & mask pgid. ceph-public-network: (string) The IP address and netmask of the public (front-side)  14 Mar 2017 Protecting data was dead center of our intention at Rackspace when we worked with Red Hat to create our Ceph Storage reference architecture. I'll need to play with pulling out the network cable or SATA cables to see how the system behaves from me causing catastrophic failures in the test system. Create a pool pointing to the new  Ceph is designed around the assumption that all components of the system (disks, hosts, networks) can fail, and has traditionally leveraged replication to provide data durability and reliability. , device, host, rack, row, room, etc. $ ceph osd erasure-code-profile set myprofile \ ruleset-failure-domain=osd $ ceph osd erasure-code-profile get myprofile k=2 m=1 plugin=jerasure technique= reed_sol_van ruleset-failure-domain=osd $ ceph osd pool create ecpool 12 12 erasure  Oct 18, 2016 Ceph is known for its “no single point of failure” mantra, but this is a “feature” configured by the administrator at many levels. ○ switches, routers. Choosing the right profile is important because it cannot be modified after the pool is created: a new pool with a different profile needs to be created and all objects from the previous pool  contain the object, and further calculates which Ceph OSD Daemon should store the placement group. Choosing the correct profile is important because you cannot change the profile after you create the pool. ceph-public-network: (string) The IP address and netmask of the public (front- side)  Feb 29, 2016 An EC pool of 4+2 chunks on a ceph cluster with a failure domain set to "host", a minimum of 6 hosts with OSDs will be needed, as we do not have 6 hosts we need to use “osd” as the failure domian which will help us to get the data striped across disks rather than hosts. 17 Jun 2013 These chassis offer a good drive/core ratio, while offering a failure domain that we are comfortable with. Ceph manages data distribution by placing OSDs in the CRUSH map hierarchy in separate buckets under a root bucket. If "none" is specified, keys will still be created and deployed so that it can be enabled later. Depending on failure domains you may wish to have single or multiple leaf  18 Jun 2014 vstart. Create a pool pointing to the new  surrounding data access, update serialization, replication and reliability, failure detection, and recovery. Lets make some change in CRUSH decompiled file. The equivalent command line parameter for this is erasure-code-directory = Default value = /usr/lib64/ceph/erasure-code ruleset-failure- domain ===> Defines the failure domain , you should set it as  Apr 20, 2017 Because you have to be able to describe the fault domains in Ceph to ensure that your failure happens exactly that way. Metadata. Ceph implements the data storage layer of file systems with the library librados, which exposes an interface to the Ceph object store. At least quad core CPU; At least 16GB RAM. . To check your cluster CRUSH map, execute the following command: # ceph osd crush dump • MDS map:  13 Nov 2017 http://docs. To check your cluster PG map, execute: # ceph pg dump • CRUSH map: This holds information of your cluster's storage devices, failure domain hierarchy, and the rules defined for the failure domain when storing data. Your example works using the OSD as the fault  Mar 14, 2017 Protecting data was dead center of our intention at Rackspace when we worked with Red Hat to create our Ceph Storage reference architecture. surrounding data access, update serialization, replication and reliability, failure detection, and recovery. By encoding this information into the cluster map, CRUSH placement policies can separate object replicas across different failure domains while still maintaining the desired distribution. FAILURE DOMAINS. For example, to address the possibility of concurrent failures, it may be desirable to ensure that data replicas are on devices using different  19 Oct 2015 However, capturing the host as a failure domain is preferred if you need to power down the host to change a drive (assuming it's not hot-swappable). The CRUSH placement algorithm is used to allow failure domains to be defined across hosts, racks, rows, or datacenters, depending  ceph osd erasure-code-profile get default directory=. 5. For added reliability and fault tolerance, Ceph supports a cluster of monitors. tier # Valid options are [ erasure, replicated ] ceph_pool_type: "erasure" # Optionally, you can change the profile #ceph_erasure_profile: "k=4 m=2 ruleset-failure-domain=host"  6 Sep 2012 Once I applied the new CRUSH map I ran a ceph -w to see that the system had detected the changes and it then started to move data around on its own. Ambedded Mars ARM based micro server reduces 80% of power  23 Oct 2017 Persistent RBD mounts. The osd_crush_location was removed in Kraken with . $ ceph osd erasure-code-profile set myprofile \ ruleset-failure-domain=osd $ ceph osd erasure-code-profile get myprofile k=2 m=1 plugin=jerasure technique=reed_sol_van ruleset-failure-domain=osd $ ceph osd pool create ecpool 12 12 erasure  18 Oct 2016 Ceph is known for its “no single point of failure” mantra, but this is a “feature” configured by the administrator at many levels. 2. The corresponding OSDs were marked out manually. When you initially set up a test cluster,  26 Sep 2017 For example, we can trivially create a “fast” pool that distributes data only over SSDs (with a failure domain of host) with the command ceph osd crush rule create-replicated <rule-name> <root> <failure-domain-type> <device-class>: $ ceph osd crush rule create-replicated fast default host ssd. And your choices to create the fault domain are the OSD, the host (with a collection of OSDs) or a rack (with a collection of hosts, etc). The paper points to Ceph being a massive failure domain (software) and how implied usage contracts might be violated by converging Block and Object storage within this failure domain. ○ Exploit CRUSH map and placement rules to define extra datacenter failure domains and placement strategies  8 Apr 2014 In most of the cases this parameter is automatically added once you define plugin name . I am going to change the CRUSH weight of an OSD. ○ physical location. Ceph is able to enable hyperscale storage via CRUSH, a hash-based algorithm for  ceph osd erasure-code-profile get default directory=. The CRUSH algorithm determines how to store and retrieve data  The core concept is that each leaf switch connects to every spine switch so that any leaf switch is only one hop anyway from any other leaf switch. ○ Deploy usually it's not so easy (port 22 closed). We operate our cluster under default CRUSHMAP with the host as a  ceph osd erasure-code-profile get default directory=. Figure 3: Files are striped across many objects, grouped into placement groups (PGs),  Ceph is designed around the assumption that all components of the system ( disks, hosts, networks) can fail, and has traditionally leveraged replication to provide data durability and reliability. So you might opt for a higher minimum failure domain in a  CRUSH maps provide the physical topology of the cluster to the CRUSH algorithm to determine where the data for an object and its replicas should be stored, and how to do so across failure domains for added data safety among other things. ○ important for declustered replication. See the documentation of the jerasure plugin for example: http://ceph. MOVE A BUCKET. ○ faster rebuild: 1/100th of disk. To view a CRUSH map, execute ceph osd getcrushmap -o { filename} ; then, decompile it by executing crushtool -d {comp-crushmap- filename} -o  Sep 26, 2017 For example, we can trivially create a “fast” pool that distributes data only over SSDs (with a failure domain of host) with the command ceph osd crush rule create-replicated : $ ceph osd crush rule create-replicated fast default host ssd. cephx; customize-failure-domain: (boolean) Setting this to true will tell Ceph to replicate across Juju's Availability Zone instead of specifically by host. BUCKET ALGORITHMS (ADVANCED)