I have a Ceph cluster running with 18 X 600GB OSDs. There are three pools (size:3, pg_num:64) with an image size of 200GB on each, and there are 6 servers connected to these images via iSCSI and storing about 20 VMs on them. Here is the output of "ceph df":
POOLS:
POOL ID STORED OBJECTS USED %USED MAX AVAIL
cephfs_data 1 0 B 0 0 B 0 0 B
cephfs_metadata 2 17 KiB 22 1.5 MiB 100.00 0 B
defaults.rgw.buckets.data 3 0 B 0 0 B 0 0 B
defaults.rgw.buckets.index 4 0 B 0 0 B 0 0 B
.rgw.root 5 2.0 KiB 5 960 KiB 100.00 0 B
default.rgw.control 6 0 B 8 0 B 0 0 B
default.rgw.meta 7 393 B 2 384 KiB 100.00 0 B
default.rgw.log 8 0 B 207 0 B 0 0 B
rbd 9 150 GiB 38.46k 450 GiB 100.00 0 B
rbd3 13 270 GiB 69.24k 811 GiB 100.00 0 B
rbd2 14 150 GiB 38.52k 451 GiB 100.00 0 B
Based on this, I expect about 1.7 TB RAW capacity usage, BUT it is currently about 9TBs!
RAW STORAGE:
CLASS SIZE AVAIL USED RAW USED %RAW USED
hdd 9.8 TiB 870 GiB 9.0 TiB 9.0 TiB 91.35
TOTAL 9.8 TiB 870 GiB 9.0 TiB 9.0 TiB 91.35
And the cluster is down because there is very few capacity remained. I wonder what makes this and how can I get it fixed.
Your help is much appreciated
The problem was mounting the iSCSI target without discard option.
Since I am using RedHat Virtualization, I just modified all storage domains created on top of Ceph, and enabled "discard" on them1. Just after a few hours, about 1 TB of storage released. Now it is about 12 hours passed and 5 TB of storage is released.
Thanks
Related
I am using unbuntu 20.04 and postgresql 12 .
My memory is 128 GB , SDD is 1TB. Cpu is i7 (16 core 20 threads)
I made simple c++ program which connect postgresql and generting tile map (just map image).
It's similar with osmtilemaker.
Once program starts, it takes serveral hours to servral months to finish job.
For first 4~5 hours, it runs well.
I monitored memory usage, and It doesnot occupy more than 10% of whole Memory at most.
Here is the screenshot of top command
Tasks: 395 total, 16 running, 379 sleeping, 0 stopped, 0 zombie
%Cpu(s): 70.3 us, 2.9 sy, 0.0 ni, 26.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 128565.5 total, 111124.7 free, 11335.7 used, 6105.1 buff/cache
MiB Swap: 2048.0 total, 2003.6 free, 44.4 used. 115108.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2217811 postgres 20 0 2369540 1.7g 678700 R 99.7 1.3 25:27.36 postgres
2217407 postgres 20 0 2393448 1.7g 678540 R 99.0 1.4 25:32.04 postgres
2217836 postgres 20 0 2352936 1.7g 679348 R 98.0 1.3 25:26.22 postgres
2217715 postgres 20 0 2368268 1.7g 680144 R 97.7 1.3 25:29.78 postgres
2217684 postgres 20 0 2384308 1.7g 679248 R 97.3 1.4 25:29.49 postgres
2217539 postgres 20 0 2386156 1.7g 680124 R 97.0 1.4 25:30.46 postgres
2216651 postgres 20 0 2429348 1.8g 678128 R 95.7 1.4 26:05.99 postgres
2217025 postgres 20 0 2396408 1.7g 679292 R 94.4 1.4 25:51.85 postgres
2238487 postgres 20 0 1294752 83724 54024 R 14.3 0.1 0:00.43 postgres
2238488 postgres 20 0 1294968 219304 189116 R 14.0 0.2 0:00.42 postgres
2238489 postgres 20 0 1294552 85624 56068 R 12.6 0.1 0:00.38 postgres
2062928 j 20 0 861492 536088 47396 S 6.6 0.4 19:18.64 mapTiler
2238490 postgres 20 0 1290132 73244 48084 R 6.3 0.1 0:00.19 postgres
2238491 postgres 20 0 1289876 73064 48160 R 6.3 0.1 0:00.19 postgres
928763 postgres 20 0 1181720 61368 59300 S 0.7 0.0 11:59.45 postgres
1306124 j 20 0 19668 2792 2000 S 0.3 0.0 0:06.84 screen
2238492 postgres 20 0 1273864 49192 40108 R 0.3 0.0 0:00.01 postgres
2238493 postgres 20 0 1273996 50172 40852 R 0.3 0.0 0:00.01 postgres
1 root 20 0 171468 9564 4864 S 0.0 0.0 0:09.40 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.02 kthreadd
I used 8 threads in program, so 8 process is using cpu a lot ,
but memory usage is always below 10%.
But, after 4~5 hours, oom-killer killed postgres processes and program stopped running.
Here is the result of dmesg
[62585.503398] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),
cpuset=/,mems_allowed=0,global_oom,
task_memcg=/system.slice/system-postgresql.slice/postgresql#12-main.service,
task=postgres,pid=463942, uid=129
[62585.503406] Out of memory: Killed process 463942 (postgres)
total-vm:19010060kB, anon-rss:17369476kB, file-rss:0kB,
shmem-rss:848380kB, UID:129 pgtables:36776kB oom_score_adj:0
It looks like out of memory error.
But, how that can happend when I have free memory more than 100GB?
Why is my ceph cluster value(964G) of raw used in global section far higher than that(244G) of used in pools section
[en#ceph01 ~]$ sudo ceph df
GLOBAL:
SIZE AVAIL RAW USED %RAW USED
6.00TiB 5.06TiB 964GiB 15.68
POOLS:
NAME ID USED %USED MAX AVAIL OBJECTS
.rgw.root 1 1.09KiB 0 1.56TiB 4
default.rgw.control 2 0B 0 1.56TiB 8
default.rgw.meta 3 0B 0 1.56TiB 0
default.rgw.log 4 0B 0 1.56TiB 207
cephfs_data 5 244GiB 9.22 2.34TiB 4829661
cephfs_meta 6 168MiB 0 2.34TiB 4160
[en#ceph01 ~]$ sudo ceph osd df
ID CLASS WEIGHT REWEIGHT SIZE USE DATA OMAP META AVAIL %USE VAR PGS
0 hdd 2.00000 1.00000 2.00TiB 331GiB 326GiB 1.64GiB 3.38GiB 1.68TiB 16.17 1.03 77
1 hdd 2.00000 1.00000 2.00TiB 346GiB 341GiB 1.69GiB 3.51GiB 1.66TiB 16.90 1.08 78
2 hdd 2.00000 1.00000 2.00TiB 286GiB 282GiB 1.31GiB 2.96GiB 1.72TiB 13.97 0.89 69
TOTAL 6.00TiB 964GiB 949GiB 4.64GiB 9.86GiB 5.06TiB 15.68
MIN/MAX VAR: 0.89/1.08 STDDEV: 1.24
info about ceph cluster:
>pool 5 'cephfs_data' replicated size 2 min_size 2 crush_rule 0 object_hash rjenkins pg_num 32 pgp_num 32 last_change 33 flags hashpspool stripe_width 0 application cephfs..
>pool 6 'cephfs_meta' replicated size 2min_size 2 crush_rule 0 object_hash rjenkins pg_num 32 pgp_num 32 last_change 31 flags hashpspool stripe_width 0 application cephfs
> max_osd 3
This is due to bluestore_min_alloc_size_hdd being most likely set at 64K.
More info here: ceph df (octopus) shows USED is 7 times higher than STORED in erasure coded pool
I am trying to get a feel for what I should expect in terms of performance from cloud storage.
I just ran the gsutil perfdiag from a compute engine instance in the same location (US) and the same project as my cloud storage bucket.
For nearline storage, I get a 25 Mibit/s read and 353 Mibit/s write, is that low / high / average, why such discrepancy between read and write ?
==============================================================================
DIAGNOSTIC RESULTS
==============================================================================
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 5 112.0 52.9 78.2 173.6
Delete 1 KiB 5 94.1 17.5 90.8 115.0
Delete 100 KiB 5 80.4 2.5 79.9 83.4
Delete 1 MiB 5 86.7 3.7 88.2 90.4
Download 0 B 5 58.1 3.8 57.8 62.2
Download 1 KiB 5 2892.4 1071.5 2589.1 4111.9
Download 100 KiB 5 1955.0 711.3 1764.9 2814.3
Download 1 MiB 5 2679.4 976.2 2216.2 3869.9
Metadata 0 B 5 69.1 57.0 42.8 129.3
Metadata 1 KiB 5 37.4 1.5 37.1 39.0
Metadata 100 KiB 5 64.2 47.7 40.9 113.0
Metadata 1 MiB 5 45.7 9.1 49.4 55.1
Upload 0 B 5 138.3 21.0 122.5 164.8
Upload 1 KiB 5 170.6 61.5 139.4 242.0
Upload 100 KiB 5 387.2 294.5 245.8 706.1
Upload 1 MiB 5 257.4 51.3 228.4 319.7
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Write throughput: 353.13 Mibit/s.
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Read throughput: 25.16 Mibit/s.
------------------------------------------------------------------------------
System Information
------------------------------------------------------------------------------
IP Address:
##.###.###.##
Temporary Directory:
/tmp
Bucket URI:
gs://pl_twitter/
gsutil Version:
4.12
boto Version:
2.30.0
Measurement time:
2015-05-11 07:03:26 PM
Google Server:
Google Server IP Addresses:
##.###.###.###
Google Server Hostnames:
Google DNS thinks your IP is:
CPU Count:
4
CPU Load Average:
[0.16, 0.05, 0.06]
Total Memory:
14.38 GiB
Free Memory:
11.34 GiB
TCP segments sent during test:
5592296
TCP segments received during test:
2417850
TCP segments retransmit during test:
3794
Disk Counter Deltas:
disk reads writes rbytes wbytes rtime wtime
sda1 31 5775 126976 1091674112 856 1603544
TCP /proc values:
wmem_default = 212992
wmem_max = 212992
rmem_default = 212992
tcp_timestamps = 1
tcp_window_scaling = 1
tcp_sack = 1
rmem_max = 212992
Boto HTTPS Enabled:
True
Requests routed through proxy:
False
Latency of the DNS lookup for Google Storage server (ms):
2.5
Latencies connecting to Google Storage server IPs (ms):
##.###.###.### = 1.1
------------------------------------------------------------------------------
In-Process HTTP Statistics
------------------------------------------------------------------------------
Total HTTP requests made: 94
HTTP 5xx errors: 0
HTTP connections broken: 0
Availability: 100%
For standard storage I get:
==============================================================================
DIAGNOSTIC RESULTS
==============================================================================
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 5 121.9 34.8 105.1 158.9
Delete 1 KiB 5 159.3 58.2 126.0 232.3
Delete 100 KiB 5 106.8 17.0 103.3 125.7
Delete 1 MiB 5 167.0 77.3 145.1 251.0
Download 0 B 5 87.2 10.3 81.1 100.0
Download 1 KiB 5 95.5 18.0 92.4 115.6
Download 100 KiB 5 156.7 20.5 155.8 179.6
Download 1 MiB 5 219.6 11.7 213.4 232.6
Metadata 0 B 5 59.7 4.5 57.8 64.4
Metadata 1 KiB 5 61.0 21.8 49.6 85.4
Metadata 100 KiB 5 55.3 10.4 50.7 67.7
Metadata 1 MiB 5 75.6 27.8 67.4 109.0
Upload 0 B 5 162.7 37.0 139.0 207.7
Upload 1 KiB 5 165.2 23.6 152.3 194.1
Upload 100 KiB 5 392.1 235.0 268.7 643.0
Upload 1 MiB 5 387.0 79.5 340.9 486.1
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Write throughput: 515.63 Mibit/s.
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Read throughput: 123.14 Mibit/s.
------------------------------------------------------------------------------
System Information
------------------------------------------------------------------------------
IP Address:
10.240.133.190
Temporary Directory:
/tmp
Bucket URI:
gs://test_throughput_standard/
gsutil Version:
4.12
boto Version:
2.30.0
Measurement time:
2015-05-21 11:08:50 AM
Google Server:
Google Server IP Addresses:
##.###.##.###
Google Server Hostnames:
Google DNS thinks your IP is:
CPU Count:
8
CPU Load Average:
[0.28, 0.18, 0.08]
Total Memory:
Upload 1 MiB 5 387.0 79.5 340.9 486.1
49.91 GiB
Free Memory:
47.9 GiB
TCP segments sent during test:
5165461
TCP segments received during test:
1881727
TCP segments retransmit during test:
3423
Disk Counter Deltas:
disk reads writes rbytes wbytes rtime wtime
dm-0 0 0 0 0 0 0
loop0 0 0 0 0 0 0
loop1 0 0 0 0 0 0
sda1 0 4229 0 1080618496 0 1605286
TCP /proc values:
wmem_default = 212992
wmem_max = 212992
rmem_default = 212992
tcp_timestamps = 1
tcp_window_scaling = 1
tcp_sack = 1
rmem_max = 212992
Boto HTTPS Enabled:
True
Requests routed through proxy:
False
Latency of the DNS lookup for Google Storage server (ms):
1.2
Latencies connecting to Google Storage server IPs (ms):
##.###.##.### = 1.3
------------------------------------------------------------------------------
In-Process HTTP Statistics
------------------------------------------------------------------------------
Total HTTP requests made: 94
HTTP 5xx errors: 0
HTTP connections broken: 0
Availability: 100%
==============================================================================
DIAGNOSTIC RESULTS
==============================================================================
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 5 145.1 59.4 117.8 215.2
Delete 1 KiB 5 178.0 51.4 190.6 224.3
Delete 100 KiB 5 98.3 5.0 96.6 104.3
Delete 1 MiB 5 117.7 19.2 112.0 140.2
Download 0 B 5 109.4 38.9 91.9 156.5
Download 1 KiB 5 149.5 41.0 141.9 192.5
Download 100 KiB 5 106.9 20.3 108.6 127.8
Download 1 MiB 5 121.1 16.0 112.2 140.9
Metadata 0 B 5 70.0 10.8 76.8 79.9
Metadata 1 KiB 5 113.8 36.6 124.0 148.7
Metadata 100 KiB 5 63.1 20.2 55.7 86.5
Metadata 1 MiB 5 59.2 4.9 61.3 62.9
Upload 0 B 5 127.5 22.6 117.4 153.6
Upload 1 KiB 5 215.2 54.8 221.4 270.4
Upload 100 KiB 5 229.8 79.2 171.6 329.8
Upload 1 MiB 5 489.8 412.3 295.3 915.4
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Write throughput: 503 Mibit/s.
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Read throughput: 1.05 Gibit/s.
------------------------------------------------------------------------------
System Information
------------------------------------------------------------------------------
IP Address:
################
Temporary Directory:
/tmp
Bucket URI:
gs://test_throughput_standard/
gsutil Version:
4.12
boto Version:
2.30.0
Measurement time:
2015-05-21 06:20:49 PM
Google Server:
Google Server IP Addresses:
#############
Google Server Hostnames:
Google DNS thinks your IP is:
CPU Count:
8
CPU Load Average:
[0.08, 0.03, 0.05]
Total Memory:
49.91 GiB
Free Memory:
47.95 GiB
TCP segments sent during test:
4958020
TCP segments received during test:
2326124
TCP segments retransmit during test:
2163
Disk Counter Deltas:
disk reads writes rbytes wbytes rtime wtime
dm-0 0 0 0 0 0 0
loop0 0 0 0 0 0 0
loop1 0 0 0 0 0 0
sda1 0 4202 0 1080475136 0 1610000
TCP /proc values:
wmem_default = 212992
wmem_max = 212992
rmem_default = 212992
tcp_timestamps = 1
tcp_window_scaling = 1
tcp_sack = 1
rmem_max = 212992
Boto HTTPS Enabled:
True
Requests routed through proxy:
False
Latency of the DNS lookup for Google Storage server (ms):
1.6
Latencies connecting to Google Storage server IPs (ms):
############ = 1.3
2nd Run:
==============================================================================
DIAGNOSTIC RESULTS
==============================================================================
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 5 91.5 14.0 85.1 106.0
Delete 1 KiB 5 125.4 76.2 91.7 203.3
Delete 100 KiB 5 104.4 15.9 99.0 123.2
Delete 1 MiB 5 128.2 36.0 116.4 170.7
Download 0 B 5 60.2 8.3 63.0 68.7
Download 1 KiB 5 62.6 11.3 61.6 74.8
Download 100 KiB 5 103.2 21.3 110.7 123.8
Download 1 MiB 5 137.1 18.5 130.3 159.8
Metadata 0 B 5 73.4 35.9 62.3 114.2
Metadata 1 KiB 5 55.9 18.1 55.3 75.6
Metadata 100 KiB 5 45.7 11.0 42.5 59.1
Metadata 1 MiB 5 49.9 7.9 49.2 58.8
Upload 0 B 5 128.2 24.6 115.5 158.8
Upload 1 KiB 5 153.5 44.1 132.4 206.4
Upload 100 KiB 5 176.8 26.8 165.1 209.7
Upload 1 MiB 5 277.9 80.2 214.7 378.5
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Write throughput: 463.76 Mibit/s.
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Read throughput: 184.96 Mibit/s.
------------------------------------------------------------------------------
System Information
------------------------------------------------------------------------------
IP Address:
#################
Temporary Directory:
/tmp
Bucket URI:
gs://test_throughput_standard/
gsutil Version:
4.12
boto Version:
2.30.0
Measurement time:
2015-05-21 06:24:31 PM
Google Server:
Google Server IP Addresses:
####################
Google Server Hostnames:
Google DNS thinks your IP is:
CPU Count:
8
CPU Load Average:
[0.19, 0.17, 0.11]
Total Memory:
49.91 GiB
Free Memory:
47.9 GiB
TCP segments sent during test:
5180256
TCP segments received during test:
2034323
TCP segments retransmit during test:
2883
Disk Counter Deltas:
disk reads writes rbytes wbytes rtime wtime
dm-0 0 0 0 0 0 0
loop0 0 0 0 0 0 0
loop1 0 0 0 0 0 0
sda1 0 4209 0 1080480768 0 1604066
TCP /proc values:
wmem_default = 212992
wmem_max = 212992
rmem_default = 212992
tcp_timestamps = 1
tcp_window_scaling = 1
tcp_sack = 1
rmem_max = 212992
Boto HTTPS Enabled:
True
Requests routed through proxy:
False
Latency of the DNS lookup for Google Storage server (ms):
3.5
Latencies connecting to Google Storage server IPs (ms):
################ = 1.1
------------------------------------------------------------------------------
In-Process HTTP Statistics
------------------------------------------------------------------------------
Total HTTP requests made: 94
HTTP 5xx errors: 0
HTTP connections broken: 0
Availability: 100%
3rd run
==============================================================================
DIAGNOSTIC RESULTS
==============================================================================
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 5 157.0 78.3 101.5 254.9
Delete 1 KiB 5 153.5 49.1 178.3 202.5
Delete 100 KiB 5 152.9 47.5 168.0 202.6
Delete 1 MiB 5 110.6 20.4 105.7 134.5
Download 0 B 5 104.4 50.5 66.8 167.6
Download 1 KiB 5 68.1 11.1 68.7 79.2
Download 100 KiB 5 85.5 5.8 86.0 90.8
Download 1 MiB 5 126.6 40.1 100.5 175.0
Metadata 0 B 5 67.9 16.2 61.0 86.6
Metadata 1 KiB 5 49.3 8.6 44.9 59.5
Metadata 100 KiB 5 66.6 35.4 44.2 107.8
Metadata 1 MiB 5 53.9 13.2 52.1 69.4
Upload 0 B 5 136.7 37.1 114.4 183.5
Upload 1 KiB 5 145.5 58.3 116.8 208.2
Upload 100 KiB 5 227.3 37.6 233.3 259.3
Upload 1 MiB 5 274.8 45.2 261.8 328.5
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Write throughput: 407.03 Mibit/s.
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied a 1 GiB file 5 times for a total transfer size of 5 GiB.
Read throughput: 629.07 Mibit/s.
------------------------------------------------------------------------------
System Information
------------------------------------------------------------------------------
IP Address:
###############
Temporary Directory:
/tmp
Bucket URI:
gs://test_throughput_standard/
gsutil Version:
4.12
boto Version:
2.30.0
Measurement time:
2015-05-21 06:32:48 PM
Google Server:
Google Server IP Addresses:
################
Google Server Hostnames:
Google DNS thinks your IP is:
CPU Count:
8
CPU Load Average:
[0.11, 0.13, 0.13]
Total Memory:
49.91 GiB
Free Memory:
47.94 GiB
TCP segments sent during test:
5603925
TCP segments received during test:
2438425
TCP segments retransmit during test:
4586
Disk Counter Deltas:
disk reads writes rbytes wbytes rtime wtime
dm-0 0 0 0 0 0 0
loop0 0 0 0 0 0 0
loop1 0 0 0 0 0 0
sda1 0 4185 0 1080353792 0 1603851
TCP /proc values:
wmem_default = 212992
wmem_max = 212992
rmem_default = 212992
tcp_timestamps = 1
tcp_window_scaling = 1
tcp_sack = 1
rmem_max = 212992
Boto HTTPS Enabled:
True
Requests routed through proxy:
False
Latency of the DNS lookup for Google Storage server (ms):
2.2
Latencies connecting to Google Storage server IPs (ms):
############## = 1.6
All things being equal, write performance is generally higher for modern storage systems because of presence of a caching layer between the application disks, that said, what you are seeing is within the expected range for "nearline" storage.
I have observed far superior throughput results when using "standard" storage buckets. Though latency did not improve much. Consider using a "Standard" bucket if your application requires high throughput. If your application is sensitive to latency, then using local storage as a cache (or scratch space) may be the only option.
Here is a snippet from one my experiments on "Standard" buckets:
------------------------------------------------------------------------------
Latency
------------------------------------------------------------------------------
Operation Size Trials Mean (ms) Std Dev (ms) Median (ms) 90th % (ms)
========= ========= ====== ========= ============ =========== ===========
Delete 0 B 10 91.5 12.4 89.0 98.5
Delete 1 KiB 10 96.4 9.1 95.6 105.6
Delete 100 KiB 10 92.9 22.8 85.3 102.4
Delete 1 MiB 10 86.4 9.1 84.1 93.2
Download 0 B 10 54.2 5.1 55.4 58.8
Download 1 KiB 10 83.3 18.7 78.4 94.9
Download 100 KiB 10 75.2 14.5 68.6 92.6
Download 1 MiB 10 95.0 19.7 86.3 126.7
Metadata 0 B 10 33.5 7.9 31.1 44.8
Metadata 1 KiB 10 36.3 7.2 35.8 46.8
Metadata 100 KiB 10 37.7 9.2 36.6 44.1
Metadata 1 MiB 10 116.1 231.3 36.6 136.1
Upload 0 B 10 151.4 67.5 122.9 195.9
Upload 1 KiB 10 134.2 22.4 127.9 149.3
Upload 100 KiB 10 168.8 20.5 168.6 188.6
Upload 1 MiB 10 213.3 37.6 200.2 262.5
------------------------------------------------------------------------------
Write Throughput
------------------------------------------------------------------------------
Copied 5 1 GiB file(s) for a total transfer size of 10 GiB.
Write throughput: 3.46 Gibit/s.
Parallelism strategy: both
------------------------------------------------------------------------------
Write Throughput With File I/O
------------------------------------------------------------------------------
Copied 5 1 GiB file(s) for a total transfer size of 10 GiB.
Write throughput: 3.9 Gibit/s.
Parallelism strategy: both
------------------------------------------------------------------------------
Read Throughput
------------------------------------------------------------------------------
Copied 5 1 GiB file(s) for a total transfer size of 10 GiB.
Read throughput: 7.04 Gibit/s.
Parallelism strategy: both
------------------------------------------------------------------------------
Read Throughput With File I/O
------------------------------------------------------------------------------
Copied 5 1 GiB file(s) for a total transfer size of 10 GiB.
Read throughput: 1.64 Gibit/s.
Parallelism strategy: both
Hope that is helpful.
I can't understand, where my ceph raw space is gone.
cluster 90dc9682-8f2c-4c8e-a589-13898965b974
health HEALTH_WARN 72 pgs backfill; 26 pgs backfill_toofull; 51 pgs backfilling; 141 pgs stuck unclean; 5 requests are blocked > 32 sec; recovery 450170/8427917 objects degraded (5.341%); 5 near full osd(s)
monmap e17: 3 mons at {enc18=192.168.100.40:6789/0,enc24=192.168.100.43:6789/0,enc26=192.168.100.44:6789/0}, election epoch 734, quorum 0,1,2 enc18,enc24,enc26
osdmap e3326: 14 osds: 14 up, 14 in
pgmap v5461448: 1152 pgs, 3 pools, 15252 GB data, 3831 kobjects
31109 GB used, 7974 GB / 39084 GB avail
450170/8427917 objects degraded (5.341%)
18 active+remapped+backfill_toofull
1011 active+clean
64 active+remapped+wait_backfill
8 active+remapped+wait_backfill+backfill_toofull
51 active+remapped+backfilling
recovery io 58806 kB/s, 14 objects/s
OSD tree (each host has 2 OSD):
# id weight type name up/down reweight
-1 36.45 root default
-2 5.44 host enc26
0 2.72 osd.0 up 1
1 2.72 osd.1 up 0.8227
-3 3.71 host enc24
2 0.99 osd.2 up 1
3 2.72 osd.3 up 1
-4 5.46 host enc22
4 2.73 osd.4 up 0.8
5 2.73 osd.5 up 1
-5 5.46 host enc18
6 2.73 osd.6 up 1
7 2.73 osd.7 up 1
-6 5.46 host enc20
9 2.73 osd.9 up 0.8
8 2.73 osd.8 up 1
-7 0 host enc28
-8 5.46 host archives
12 2.73 osd.12 up 1
13 2.73 osd.13 up 1
-9 5.46 host enc27
10 2.73 osd.10 up 1
11 2.73 osd.11 up 1
Real usage:
/dev/rbd0 14T 7.9T 5.5T 59% /mnt/ceph
Pool size:
osd pool default size = 2
Pools:
ceph osd lspools
0 data,1 metadata,2 rbd,
rados df
pool name category KB objects clones degraded unfound rd rd KB wr wr KB
data - 0 0 0 0 0 0 0 0 0
metadata - 0 0 0 0 0 0 0 0 0
rbd - 15993591918 3923880 0 444545 0 82936 1373339 2711424 849398218
total used 32631712348 3923880
total avail 8351008324
total space 40982720672
Raw usage is 4x real usage. As I understand, it must be 2x ?
Yes, it must be 2x. I don't really shure, that the real raw usage is 7.9T. Why do you check this value on mapped disk?
This are my pools:
pool name KB objects clones degraded unfound rd rd KB wr wr KB
admin-pack 7689982 1955 0 0 0 693841 3231750 40068930 353462603
public-cloud 105432663 26561 0 0 0 13001298 638035025 222540884 3740413431
rbdkvm_sata 32624026697 7968550 31783 0 0 4950258575 232374308589 12772302818 278106113879
total used 98289353680 7997066
total avail 34474223648
total space 132763577328
You can see, that the total amount of used space is 3 times more than the used space in the pool rbdkvm_sata (+-).
ceph -s shows the same result too:
pgmap v11303091: 5376 pgs, 3 pools, 31220 GB data, 7809 kobjects
93736 GB used, 32876 GB / 123 TB avail
I don't think you have just one rbd image. The result of "ceph osd lspools" indicated that you had 3 pools and one of pools had name "metadata".(Maybe you were using cephfs). /dev/rbd0 was appeared because you mapped the image but you could have other images also. To list the images you can use "rbd list -p ". You can see the image info with "rbd info -p "
i have an installation on memcache which i want to use in my production environment but when i have ran a couple of tests it seems that memcache doesn't free up memory even after it has used up all of it allocated memory, Also i logged in and ran a flush_all command but the objects are still in the cache.
Here are outputs from some tests
memcached-tool
memcache-top v0.6 (default port: 11211, color: on, refresh: 3 seconds)
INSTANCE USAGE HIT % CONN TIME EVICT/s READ/s WRITE/s
127.0.0.1:11211 427.1% 0.0% 18 1.4ms 0.0 244 261.0K
AVERAGE: 427.1% 0.0% 18 1.4ms 0.0 244 261.0K
TOTAL: 4.3MB/ 1.0MB 18 1.4ms 0.0 244 261.0K
memcached-tool 127.0.0.1:11211 display
No Item_Size Max_age Pages Count Full? Evicted Evict_Time OOM
1 560B 4s 1 1872 yes 0 0 15488
2 704B 32s 1 559 no 0 0 0
3 880B 4s 1 1191 yes 0 0 1335
4 1.1K 9s 1 116 no 0 0 0
5 1.4K 21s 1 14 no 0 0 0
6 1.7K 4s 1 17 no 0 0 0
7 2.1K 84s 1 24 no 0 0 0
8 2.7K 130s 1 60 no 0 0 0
9 3.3K 25s 1 290 no 0 0 0
10 4.2K 9s 1 194 no 0 0 0
11 5.2K 9s 1 116 no 0 0 0
15 12.7K 816s 1 1 no 0 0 0
16 15.9K 769s 1 5 no 0 0 0
18 24.8K 786s 1 1 no 0 0 0
21 48.5K 816s 1 1 no 0 0 0
memcached-tool 127.0.0.1:11211 stats
127.0.0.1:11211 Field Value
accepting_conns 1
auth_cmds 0
auth_errors 0
bytes 4478060
bytes_read 23964596
bytes_written 546642860
cas_badval 0
cas_hits 0
cas_misses 0
cmd_flush 0
cmd_get 240894
cmd_set 4504
conn_yields 0
connection_structures 21
curr_connections 18
curr_items 4461
decr_hits 0
decr_misses 0
delete_hits 0
delete_misses 0
evictions 0
get_hits 43756
get_misses 197138
incr_hits 0
incr_misses 0
limit_maxbytes 1048576
listen_disabled_num 0
pid 8731
pointer_size 64
reclaimed 0
rusage_system 5.047232
rusage_user 4.311344
threads 4
time 1306247929
total_connections 3092
total_items 4504
uptime 1240
version 1.4.5
-m tells memcached how much RAM to use for item storage (in megabytes). Note
carefully that this isn't a global
memory limit, so memcached will use a
few % more memory than you tell it to.
Set this to safe values. Setting it to
less than 48 megabytes does not work
properly in 1.4.x and earlier. It will
still use the memory.
Source: https://github.com/memcached/memcached/wiki/ConfiguringServer#commandline-arguments