DokuWiki

A document for me to recall and make notes of what I read in the manual pages and what needs testing.

Basically during the Summer of 2016 I investigated if the HPCC could afford enterprise level storage. I wanted 99.999% uptime, snapshots, high availability and other goodies such as parallel NFS. Netapp came the closest but, eh, still at $42K lots of other options show up. The story is detailed here at The Storage Problem

This page is best read from the bottom up.

• Storage servers: buy 2 now 4k+4k then 3rd in July 4k?

• move test users over on 2 nodes, test, only change is $HOME

• Home cluster
  • cottontail (mngt+admingiu)
  • 2-3 new units storage (+snapshots/meta backup)
  • cottontail2 meta + n38-n45 meta, all mirrored

Definitely wnat Meta content mirrored, that way you use the n38-n45 nodes with local 15K disk, plus maybe cottontail2 (raid 1 with hot and cold spare).

Content mirrorring will require more disk space. Perhaps snapshotting to another node is more useful, also solves backup issue. -

# enable
[root@n7 ~]# beegfs-ctl --mirrormd /mnt/beegfs/hmeij-mirror
Mount: '/mnt/beegfs'; Path: '/hmeij-mirror'
Operation succeeded.

# put some new content in 
[root@n7 ~]# rsync -vac /home/hmeij/iozone-tests /mnt/beegfs/hmeij-mirror/

# lookup meta tag
[root@n7 ~]# beegfs-ctl --getentryinfo /mnt/beegfs/hmeij-mirror/iozone-tests/current.tar
Path: /hmeij-mirror/iozone-tests/current.tar
Mount: /mnt/beegfs
EntryID: 3-581392E1-31

# find
[root@sharptail ~]# ssh n38 find /data/beegfs_meta -name 3-581392E1-31
/data/beegfs_meta/mirror/49.dentries/54/6C/0-581392F0-30/#fSiDs#/3-581392E1-31

# and find
[root@sharptail ~]# ssh n39 find /data/beegfs_meta -name 3-581392E1-31
/data/beegfs_meta/dentries/54/6C/0-581392F0-30/#fSiDs#/3-581392E1-31

# seems to work

• Source content 110G in XFS with ~100,000 files in ~2,000 dirs
  • /home/hmeij (mix of files, nothing large) plus
  • /home/fstarr/filler (lots of tiny files)

• File content spread across 2 storage servers
• petaltail:/var/chroot/data/beegfs_storage
• swallowtail:/data/beegfs_storage
• 56G used in beegfs-storage per storage server
• ~92,400 files per storage server
• ~1,400 dirs per storage server mostly in “chunks” dir

• Meta content spread across 2 meta servers (n37 and n38)
  • 338MB per beegfs-meta server so 0.006% space wise for 2 servers
  • ~105,000 files per metadata server
  • ~35,000 dirs almost spread evenly across “dentries” and “inodes”

• Client (n7 and n8) see 110G in /mnt/beegfs
  • 110G in /mnt/beegfs
  • ~100,000 files
  • ~2,000 dirs

Looks like:

# file content

[root@swallowtail ~]# ls -lR /data/beegfs_storage/chunks/u0/57E4/2/169-57E42E75-31
/data/beegfs_storage/chunks/u0/57E4/2/169-57E42E75-31:
total 672
-rw-rw-rw- 1 root root 289442 Jun 26  2015 D8-57E42E89-30
-rw-rw-rw- 1 root root   3854 Jun 26  2015 D9-57E42E89-30
-rw-rw-rw- 1 root root  16966 Jun 26  2015 DA-57E42E89-30
-rw-rw-rw- 1 root root  65779 Jun 26  2015 DB-57E42E89-30
-rw-rw-rw- 1 root root  20562 Jun 26  2015 DF-57E42E89-30
-rw-rw-rw- 1 root root 259271 Jun 26  2015 E0-57E42E89-30
-rw-rw-rw- 1 root root    372 Jun 26  2015 E1-57E42E89-30

[root@petaltail ~]# ls -lR /var/chroots/data/beegfs_storage/chunks/u0/57E4/2/169-57E42E75-31
/var/chroots/data/beegfs_storage/chunks/u0/57E4/2/169-57E42E75-31:
total 144
-rw-rw-rw- 1 root root     40 Jun 26  2015 DC-57E42E89-30
-rw-rw-rw- 1 root root  40948 Jun 26  2015 DD-57E42E89-30
-rw-rw-rw- 1 root root 100077 Jun 26  2015 DE-57E42E89-30

# meta content

[root@sharptail ~]# ssh n38 find /data/beegfs_meta -name 169-57E42E75-31
/data/beegfs_meta/inodes/6A/7E/169-57E42E75-31
/data/beegfs_meta/dentries/6A/7E/169-57E42E75-31

[root@sharptail ~]# ssh n39 find /data/beegfs_meta -name 169-57E42E75-31
(none, no mirror)

• global interfaces files ib0→eth1→eth0
  • connInterfacesFile = /home/tmp/global/beegfs.connInterfacesFile
  • set in /etc/beegfs-[storage|client|meta|admon|mgmtd].conf and restart services

• backup beeGFS EA metadata, see faq
  • attempt a restore
  • or just snapshot

• storage server tuning
  • set on cottontail on sdb, both values were 128 (seems to help – late summer 2016)
  • echo 4096 > /sys/block/sd?/queue/nr_requests
  • echo 4096 > /sys/block/sd?/queue/read_ahead_kb
  • set on cottontail, was 90112 + /etc/rc.local
  • echo 262144 > /proc/sys/vm/min_free_kbytes
• do same on greentail? (done late fall 2016)
  • all original values same as cottontail (all files)
  • set on c1d1 thru c1d6
• do same on sharptail?
  • no such values for sdb1
  • can only find min_free_kbytes, same value as cottontail
• stripe and chunk size

[root@n7 ~]# beegfs-ctl --getentryinfo /mnt/beegfs/
Path:
Mount: /mnt/beegfs
EntryID: root
Metadata node: n38 [ID: 48]
Stripe pattern details:
+ Type: RAID0
+ Chunksize: 512K
+ Number of storage targets: desired: 4

• The cache type can be set in the client config file (/etc/beegfs/beegfs-client.conf).
  • buffered is default, few 100k per file

• tuneNumWorkers in all /etc/beegfs/beggfs-C.conf file
  • for meta, storage and clients …

• metadata server tuning
  • read in more detail

• made easy External Link
• rpms pulled from repository via petaltail in greentail:/sanscratch/tmp/beegfs

[root@cottontail ~]# ssh n7 beegfs-net

mgmt_nodes
=============
cottontail [ID: 1]
   Connections: TCP: 1 (10.11.103.253:8008); 

meta_nodes
=============
n38 [ID: 48]
   Connections: TCP: 1 (10.11.103.48:8005); 
n39 [ID: 49]
   Connections: TCP: 2 (10.11.103.49:8005); 

storage_nodes
=============
swallowtail [ID: 136]
   Connections: TCP: 1 (192.168.1.136:8003 [fallback route]); 
petaltail [ID: 217]
   Connections: <none>

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