Hello, you need all of these:
In job director section:
- Spool Data = yes, attribute spooling is automatically enabled too
In device storage section:
- Maximum File Size = 32 GB, for LTO-6 and older you can think about 16 GB
- Sufficient Maximum Job Spool Size or Maximum Spool Size, so overall write
speed
could be effective, I use 200 GB and 1000 GB
- Maximum Block Size = 262144 or 131072, for LTO-6 and older 65536 (this is
tested
on my FreeBSD system, Linux or another systems may need higher values - but
do not
use too big, because probability of write errors increases)
- SSD based disk spooling, M2 or SATA RAID
I finished write speed tests with different file sizes, so here they are
(+ is my recommended file size, - is alternative and I expect that LTO-9
is still similar to LTO-8 and LTO-7 in this view):
LTO-5, block size 65536:
File Simplified Simplified Bytes Files Rough time to
size fill time fill rate written written read one file
(at 140 MB/s)
1 GB 6:44:18 61.8 MB/s 1498688192512 1499 00:00:07
2 GB 4:51:30 85.7 MB/s 1498737278976 750 00:00:14
4 GB 3:54:57 106.3 MB/s 1498762641408 375 00:00:29
8 GB 3:24:22 122.2 MB/s 1499224932352 188 00:00:57
16 GB + 3:11:09 130.7 MB/s 1499456405504 94 00:01:54
32 GB - 3:04:35 135.4 MB/s 1499690303488 47 00:03:49
64 GB 3:01:17 137.8 MB/s 1499574960128 24 00:07:37
128 GB 2:59:37 139.1 MB/s 1499603664896 12 00:15:14
LTO-6, block size 65536:
File Simplified Simplified Bytes Files Rough time to
size fill time fill rate written written read one file
(at 160 MB/s)
1 GB 9:51:38 70.4 MB/s 2500322394112 2501 00:00:06
2 GB 7:05:45 97.9 MB/s 2500404314112 1251 00:00:13
4 GB 5:42:29 121.6 MB/s 2500445274112 626 00:00:25
8 GB 4:56:39 140.5 MB/s 2501218009088 313 00:00:50
16 GB + 4:37:28 150.2 MB/s 2501603885056 157 00:01:40
32 GB - 4:27:55 155.6 MB/s 2501608472576 79 00:03:20
64 GB 4:24:19 157.7 MB/s 2501801803776 40 00:06:40
128 GB 4:20:58 159.7 MB/s 2501995266048 20 00:13:20
256 GB 4:19:43 160.5 MB/s 2501779521536 10 00:26:40
LTO-7, block size 262144 (65536 started to be limiting):
File Simplified Simplified Bytes Files Rough time to
size fill time fill rate written written read one file
(at 300 MB/s)
2 GB 9:17:20 179.8 MB/s 6013258301440 3007 00:00:07
4 GB 7:25:39 224.8 MB/s 6013256204288 1504 00:00:13
8 GB 6:30:19 256.9 MB/s 6017229258752 753 00:00:27
16 GB 6:02:51 276.3 MB/s 6015444844544 376 00:00:53
32 GB + 5:48:56 287.4 MB/s 6017326514176 189 00:01:47
64 GB - 5:42:07 293.1 MB/s 6017325989888 95 00:03:33
128 GB 5:38:45 296.0 MB/s 6017107623936 48 00:07:07
256 GB 5:36:56 297.6 MB/s 6017456013312 24 00:14:13
512 GB 5:36:12 298.3 MB/s 6017455751168 12 00:28:27
LTO-8, block size 262144:
File Simplified Simplified Bytes Files Rough time to
size fill time fill rate written written read one file
(at 300 MB/s)
2 GB 17:59:35 185.3 MB/s 12005379407872 6004 00:00:07
4 GB 14:34:50 228.7 MB/s 12005942231040 3002 00:00:13
8 GB 12:52:26 259.2 MB/s 12013881786368 1502 00:00:27
16 GB 12:01:17 277.5 MB/s 12010304307200 751 00:00:53
32 GB + 11:35:37 287.8 MB/s 12012189122560 376 00:01:47
64 GB - 11:26:04 291.8 MB/s 12014075510784 188 00:03:33
128 GB 11:16:23 296.0 MB/s 12014574370816 94 00:07:07
256 GB 11:13:14 297.4 MB/s 12014339227648 47 00:14:13
512 GB 11:11:39 298.1 MB/s 12013157220352 24 00:28:27
Pierre Bernhardt wrote (2024/01/25):
> Am 25.01.24 um 10:06 schrieb Marco Gaiarin:
> >
> > > 2) checked disk performance (data came only from local disk); i've
> > > currently
> > > 3 servers, some perform better, some worster, but the best one have a
> > > read
> > > disk performance pretty decent, at least 200MB/s on random access (1500
> > > MB/s
> > > on sequential one).
> >
> > Jim Pollard on private email ask me about controllers: i've not specified,
> > sorry, but LTO units are connected to a specific SAS controller, not the
> > disks one.
> >
> I'm registred also a lower than expected write performance.
> My LTO-6 drive should be handle 160 MB/s uncompressable random data.
> By the way mostly bacula said after writing a sequence that the tranfer speed
> is mostly round about 80 MB/s.
> I've not investigated yet but normally it should go faster. The job is spooled
> to /tmp and the swap is not in use. So the Transfer should be much more
> faster.
>
> My suggestion now is:
>
> Create a big data-random file as like a spool file in /tmp.
> Spool it with dd from tmp to /dev/null
> Spool from /dev/random to tape
> Spool from /tmp to tape
>
> Any suggestions about bs usage or something else?
>
> Pierre
--
Rudolf Cejka <cejkar at fit.vut.cz> https://www.fit.vut.cz/~cejkar
Brno University of Technology, Faculty of Information Technology
Bozetechova 1/2, 612 00 Brno, Czech Republic
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